45669583 Organic Practice

956
Chapter 1 1 MULTIPLE CHOICE QUESTIONS Topic: Atomic Orbitals 1. In quantum mechanics a node (nodal surface or plane) is: A) a place where Ψ is negative. B) a place where Ψ is positive. C) a place where Ψ = 0. D) a place where Ψ 2 is large. E) a place where Ψ 2 is negative. Ans: C Topic: Atomic Orbitals, Molecular Orbitals 2. When the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule, how many molecular orbitals are formed? A) 1 B) 2 C) 3 D) 4 E) 5 Ans: B Topic: Atomic Orbitals 3. Which principle(s) or rule must be used to determine the correct electronic configuration for carbon in its ground state? A) Aufbau Principle B) Hund's Rule C) Pauli Exclusion Principle D) (A) and (B) only E) All three Ans: E

Transcript of 45669583 Organic Practice

Page 1: 45669583 Organic Practice

Chapter 1

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MULTIPLE CHOICE QUESTIONS Topic: Atomic Orbitals

1. In quantum mechanics a node (nodal surface or plane) is: A) a place where Ψ is negative. B) a place where Ψ is positive. C) a place where Ψ = 0. D) a place where Ψ2 is large. E) a place where Ψ2 is negative.

Ans: C Topic: Atomic Orbitals, Molecular Orbitals

2. When the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule, how many molecular orbitals are formed?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B Topic: Atomic Orbitals

3. Which principle(s) or rule must be used to determine the correct electronic configuration for carbon in its ground state?

A) Aufbau Principle B) Hund's Rule C) Pauli Exclusion Principle D) (A) and (B) only E) All three

Ans: E

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Topic: Atomic Orbitals, Bonding

4. What point on the potential energy diagram below represents the most stable state for the hydrogen molecule?

A) I B) II C) III D) IV E) V

Ans: C Topic: Atomic Orbitals, Molecular Orbitals

5. According to molecular orbital theory, which molecule could not exist? A) H2 B) He2 C) Li2 D) F2 E) N2

Ans: B Topic: Atomic Orbitals, Molecular Orbitals

6. When the ls orbitals of two hydrogen atoms combine to form a hydrogen molecule, which molecular orbitals are formed?

A) One bonding molecular orbital only B) Two bonding molecular orbitals C) One bonding molecular orbital and one antibonding molecular orbital D) Two antibonding molecular orbitals E) Three bonding molecular orbitals

Ans: C

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Topic: Atomic Orbitals, Hybridization

7. The following electron configuration represents _______.

1s 2sp32sp32sp32sp3

A) the ground state of boron. B) the sp3 hybridized state of carbon. C) the sp3 hybridized state of nitrogen. D) the ground state of carbon. E) an excited state of carbon.

Ans: C Topic: Atomic Orbitals, Molecular Orbitals

8. According to molecular orbital theory, in the case of a carbon-carbon double bond, the carbon-carbon bonding electrons of higher energy occupy this molecular orbital.

A) σ bonding MO B) π bonding MO C) σ* antibonding MO D) π* antibonding MO E) π* bonding MO

Ans: B Topic: Atomic Orbitals, Hybridization

9. Identify the atomic orbitals in the C-C sigma bond in ethyne. A) (2sp2, 2sp2) B) (2sp3, 2sp3) C) (2sp, 2sp) D) (2p, 2p) E) (2sp, 1s)

Ans: C

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Topic: Lewis Structures, Formal Charges

10. Listed below are electron dot formulas for several simple molecules and ions. All valence electrons are shown; however, electrical charges have been omitted deliberately.

H H H H

HH

I II III IV V

H : Be : H H : B : H H : N : H H : N : H H : O : H. .. .. .. .

. . . . . . . .

Which of the structures actually bear(s) a positive charge?

A) I B) II C) III D) III & V E) IV & V

Ans: E Topic: Lewis Structures, Formal Charges

11. What is the formal charge on oxygen in the following structure? OH3C CH3

CH3

. .

A) +2 B) +1 C) 0 D) -1 E) -2

Ans: B

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Topic: Lewis Structures, Formal Charges

12. In which structure(s) below does the oxygen have a formal charge of +1?

OC HHOHOH H

H

OH3C CH3

CH3

II III IVI

. .. .. .. .:. .

H

s

A) I only B) II only C) I and III D) I and IV E) I, III, and IV

Ans: E Topic: Lewis Structures, Formal Charges

13. Which structure(s) contain(s) an oxygen that bears a formal charge of +1?

OH3C CH3

CH3

IV

OH3C H

HIII

OCO

II

O

CH

O

I

O

C

O

O

V

. .. .. .::. .

. .

. .

::

:

. .

. .

::

:

. . ::

A) I and II B) III and IV C) V D) II E) I and V

Ans: B

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Topic: Lewis Structures, Formal Charges

14. Which of the following molecules or ions has a nitrogen with a formal charge of -1? (Charges on ions have been omitted.)

A) N H

H

. .:

B) NH H

H

. .

C) NH CH3

H

. .

D) NH3C CH3

H

. .

E) CH3C N:

Ans: A Topic: Lewis Structures, Formal Charges

15. In which structure(s) below does nitrogen have a formal charge of +1?

NH3C CH3

CH3

NH3C CH2

H

NH3C H NH2H3C

IVIIIIII V

NH

OHH

. .. . . .. .

. . . .. .

A) I B) II and IV C) III and V D) I and V E) V

Ans: A

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Topic: Lewis Structures, Formal Charges

16. Which of the following is an ion with a single negative charge? A) OH3C

. .:. .

B) ONO. .

::. .. .

. .

C)

ONO

O

. .

. .

::

: ::

. .

D) All of these E) None of these

Ans: D Topic: Lewis Structures, Formal Charges

17. Which of these is a correct electron-dot representation of the nitrite ion, NO2-?

IV

IIIIII

V

: O : N : : O : O : : N : O : : O : : N : : O

: O : N : O : : O : : N : O

. .

. .. . . .

. .. .. . . .

. . . .. .

. .. .

. .. . . .

. .. . . . . . . .. .. .

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Lewis Structures, Formal Charges

18. Which is NOT a correct Lewis structure? A) NH F

H

. .. . :

B)

CH F

H

H

:....

C) OH O

. .

. . H. .. .

D)

OBO

O

. .

. .

:

:. .. .H

H

H E) None of these

Ans: A Topic: Lewis Structures, Formal Charges

19. Listed below are electron dot formulas for several simple molecules and ions. All valence electrons are shown; however, electrical charges have been omitted deliberately.

H H H H

HH

I IV VII III

H : Be : H H : B : H H : N : H H : N : H H : O : H. .. .. .. .

. . . . . . . .

Which of the structures is negatively charged?

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Lewis Structures, Formal Charges

20. Which compound contains a nitrogen atom with a formal positive charge?

HN N

N

I II III

A) I B) II C) III D) More than one of the above E) None of the above

Ans: D Topic: Lewis Structures

21. Considering Lewis structures, which of these compounds possesses a single unpaired electron?

A) N2 B) N2O C) NO D) N2O4 E) O2

Ans: C Topic: Lewis Structures

22. Y

ZY

..

.. is a generalized structural representation which can be used for all of the following, except:

A) OF2 B) NH2

– C) H2S D) BeBr2 E) There is no exception

Ans: D

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Topic: Lewis Structures, Formal Charges

23. In which of these cases does the central atom have a zero formal charge? A) HFH B)

OH3C CH3

H

C)

BF F

F

F D)

NH3C CH3

H

H E)

CH3C CH3

CH3

CH3 Ans: E

Topic: Lewis Structures, Formal Charges

24. The formal charge on sulfur in sulfuric acid is:

SO O

O

O

H H

A) 0 B) -1 C) +1 D) -2 E) +2

Ans: A Topic: Lewis Structures, Formal Charges

25. ExpAns:ion of the valence shell to accommodate more than eight electrons is possible with:

A) Fluorine B) Nitrogen C) Carbon D) Sulfur E) Beryllium

Ans: D

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Topic: Lewis Structures, Molecular Geometry

26. Based on VSEPR theory, which of the following would have a trigonal planar shape? A) CH3)3N B) HCN C) NH4

+ D) CH3

− E) CH3

+ Ans: E

Topic: Lewis Structures, Molecular Geometry

27. VSEPR theory predicts an identical shape for all of the following, except: A) NH3 B) H3O+ C) BH3 D) CH3

- E) All have the same geometry

Ans: C Topic: Lewis Structures, Molecular Geometry

28. What shape does the methyl cation, CH3+, have?

A) Octahedral B) Tetrahedral C) Trigonal planar D) Linear E) Trigonal pyramidal

Ans: C

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Topic: Lewis Structures, Molecular Geometry

29. Which of the structures below would be trigonal planar (a planar triangle)? (Electrical charges have been deliberately omitted.)

F

F

I II III

F

F

IV

H

H

HB : F. .. . :

..

..

: ....: ....

H : O : H H : C : F : N :. .. .:

. .

. .

: ....: ....

..

......

A) I B) II C) III D) IV E) I and IV

Ans: A Topic: Lewis Structures, Molecular Geometry

30. Which of the following would have a trigonal planar (or triangular) structure?

I II III IV V: CH3 : CH3 : NH3 : OH3BH3

A) I, II, and IV B) II and IV C) IV D) II, IV, and V E) All of these

Ans: B Topic: Molecular Geometry

31. What bond angle is associated with a tetrahedral molecule? A) 120° B) 109.5° C) 180° D) 90° E) 45°

Ans: B

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Topic: Molecular Geometry

32. What would be the spatial arrangement of the atoms of the methyl anion, :CH3-?

A) Octahedral B) Tetrahedral C) Trigonal planar D) Linear E) Trigonal pyramidal

Ans: E Topic: Lewis Structures, Molecular Geometry

33. Which of these structures would be a perfectly regular tetrahedron? A) CH3Br B) CH2Br2 C) CHBr3 D) CBr4 E) More than one of these

Ans: D Topic: Lewis Structures, Molecular Geometry

34. Which molecule would be linear? (In each case you should write a Lewis structure before deciding.)

A) SO2 B) HCN C) H2O2 D) H2S E) OF2

Ans: B Topic: Lewis Structures, Molecular Geometry

35. The bond angles in PH3 would be expected to be approximately: A) 60° B) 90° C) 105° D) 109° E) 120°

Ans: C

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Topic: Periodic Properties, Electronegativity

36. Select the most electronegative element. A) H B) O C) N D) B E) C

Ans: N Topic: Atomic Orbitals, Hybridization

37. Select the hybridized atomic orbital.

I II III IV V

A) I B) II C) III D) IV E) V

Ans: C Topic: Atomic Orbitals, Hybridization

38. How many 2p atomic orbitals from boron must be mixed with a 2s atomic orbital to yield the bonding hybrid atomic orbitals in BF3?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B

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Topic: Atomic Orbitals, Hybridization

39. In which molecule is the central atom sp3 hybridized? A) CH4 B) NH3 C) H2O D) All of these E) None of these

Ans: D Topic: Atomic Orbitals, Hybridization

40. In which of the following would you expect the central atom to be sp3 hybridized (or approximately sp3 hybridized)?

A) BH4-

B) NH4+

C) CCl4 D) CH3:- E) All of these

Ans: D Topic: Atomic orbitals, hybridization

41. Which compound has the shortest carbon-carbon bond(s)? A) CH3CH3 B) CH2=CH2 C) HC≡CH D) CH3CH2CH3 E) All carbon-carbon bonds are the same length.

Ans: C Topic: Atomic Orbitals, Hybridization

42. Which of the following contains an sp2-hybridized carbon? A) CH4 B) CH3:− C) CH3CH3 D) CH3

+ E) HC≡CH

Ans: D

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Topic: Atomic Orbitals, Hybridization

43. Which is the shortest of the carbon-carbon single bonds indicated by arrows in the following compounds?

A)

H3C CH3 B)

H3C C CH C)

H3C CH

CH2

D)

HC C C CH E) H2C

HC C CH Ans: D

Topic: Atomic Orbitals, Hybridization

44. How many sigma (1s-2sp3) bonds are there in ethane? A) 7 B) 6 C) 5 D) 3 E) 1

Ans: B Topic: Atomic Orbitals, Bonding

45. Which of these substances contains both covalent and ionic bonds? A) NH4Cl B) H2O2 C) CH4 D) HCN E) H2S

Ans: A

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Topic: Atomic Orbitals, Periodic Trends, Electronegativity

46. The greatest degree of ionic character is anticipated for the bond between: A) H and C B) H and Cl C) C and Cl D) H and Br E) Br and Cl

Ans: B Topic: Atomic Orbitals, Hybridization

47. Which molecule contains an sp-hybridized carbon? A) HCN B) CH2=CH2 C) CH3Cl D) H

C O

H E) CH3CH3

Ans: A Topic: Atomic Orbitals, Lewis structures, Resonance

48. Which of the structures below is not expected to contribute to the CO2 resonance hybrid?

A) O C O

B) O C O C) O C O D) O C O E)

O C O Ans: D

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Topic: Atomic orbitals, Lewis structures, resonance

49. Which of the following could not be a resonance structure of CH3NO2? A)

C

H

H

H

N

O

O

: ....

..

..

B)

C

H

H

H

NO

O

: ....: ..

C)

C

H

H

H

NO

O

: ....: ....

+2

D)

C

H

H

H

NO

O

H

: ....

..

.. E) Both C and D

Ans: D Topic: Atomic Orbitals, Lewis Structures, Resonance

50. Which of the following pairs are NOT resonance structures? A)

H3C O N O: : :

: : H3C O N O

: : :

:and :

B)

:....O C O O C Oand

: ..

:..

:..

C)

H3C O N O

: : :

: : H3C NO

O: ........

and

D) Each of these pairs represents resonance structures. E) None of these pairs represents resonance structures.

Ans: C

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Topic: Atomic Orbitals, Lewis Structures, Resonance

51. How many resonance structures can be written for the NO3- ion in which the nitrogen

atom bears a formal charge of +1? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C Topic: Empirical and Molecular Formulas

52. What is the empirical formula for cyclohexane? (Its molecular formula is C6H12.) A) CH B) CH2 C) C2H4 D) C6H6 E) C2H2

Ans: B Topic: Empirical and Molecular Formulas

53. A compound has the empirical formula, CCl. Its molecular weight is 285 +/- 5. What is the molecular formula for the compound?

A) C2Cl2 B) C3Cl3 C) C4Cl4 D) C5Cl5 E) C6Cl6

Ans: E Topic: Empirical and Molecular Formulas

54. A compound consists only of carbon, hydrogen and oxygen. Elemental analysis gave: C, 70.5%, H, 13.8%. The molecular weight of the compound was found to be 103 +/- 3. What is the molecular formula for the compound?

A) C6H12O B) C5H12O2 C) C3H2O4 D) C3H6O3 E) C6H14O

Ans: E

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Topic: Isomerism

55. Which of the following is a set of constitutional isomers?

Br Br

Br

Br

IVIIIIII

A) I and II B) II and III C) I, II, and III D) II, III, and IV E) I, III, and IV

Ans: E Topic: General

56. Credit for the first synthesis of an organic compound from an inorganic precursor is usually given to:

A) Berzelius B) Arrhenius C) Kekule D) Wohler E) Lewis

Ans: D Topic: Isomerism

57. CH3CH2OCH2CH3 and CH3CH2CH2CH2OH are examples of what are now termed: A) Structural isomers B) Resonance structures C) Functional isomers D) Empirical isomers E) Constitutional isomers

Ans: E

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Topic: Hybridization

58. What is the approximate hybridization state of the oxygen molecule in ethanol, C2H5OH?

A) sp B) sp2 C) sp3 D) p3 E) d2sp3

Ans: C Topic: Hybridization

59. What is the approximate hybridization state of the oxygen molecule in trimethylamine, (CH3)3N?

A) sp B) sp2 C) sp3 D) p3 E) d2sp3

Ans: C Topic: Lewis structures, Hybridization

60. Which molecule has a non-linear structure (i.e., for which molecule are the nuclei not in a straight line)?

A) O=C=O B) H–O–H C) H–Cl D) H–C≡N E) H–C≡C–H

Ans: B

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Topic: Isomerism

61. Which of the following structures represent compounds that are constitutional isomers of each other?

IIIIII IV

A) I and II B) I and III C) I, II, and III D) I, II, III, and IV E) II and III

Ans: C Topic: Isomerism

62. Which compound is not an isomer of the others?

OO

IIIIII IV

OHOH

A) I B) II C) III D) IV E) All of the above are isomers of each other.

Ans: A

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Topic: Isomerism

63. Consider the following:

CH3CH2CH=CHCH2CH3 CH3CH2CH2CH2CH=CH2I II

CH3CH=CHCH2CH2CH3 CH2=CHCH2CH2CH2CH3III IV

Which two structures represent the same compound?

A) I and II B) II and III C) I and III D) II and IV E) None of these

Ans: D Topic: Isomerism

64. Consider the following: CH3CH2CH2CH=CHCH2CH2CH3 CH3CH2CH2CH2CH2CH2CH=CH2

I II

CH3CH2CH=CHCH2CH2CH2CH3 CH2=CHCH2CH2CH2CH2CH2CH3 III IV

Which structures can exist as cis-trAns: isomers?

A) I and II B) I and III C) I and IV D) II and III E) I alone

Ans: B

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Topic: Isomerism

65. Which of the following represent a pair of constitutional isomers? A)

and B) CH3CH=CH2 and CH2=CHCH3 C)

H

Br

Br

H

Br

Br

H

H

and

D)

Br

Br

H

H

H

Br

H

Br

and

E) More than one of these Ans: E

Topic: Isomerism

66. Which of the following represent pairs of constitutional isomers? A) OH

O O

O

andB)

H

CH3

Br

H

Br

CH3

H

H

and

C)

Br CH3

CH2

H

Br

H

CH3

and

D) More than one of these pairs E) All of these pairs

Ans: D Topic: Isomerism

67. Cis-trAns: isomerism is possible only in the case of: A) CH2=CBr2 B) CH2=CHBr C) BrCH=CHBr D) Br2C=CHBr E) Br2C=CBr2

Ans: C

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Topic: Atomic orbitals, molecular orbitals

68. When the 1s orbitals of two hydrogen atoms combine to form a hydrogen molecule, how are the electrons distributed in the resulting molecular orbitals?

A) 2 electrons in the bonding molecular orbital B) 1 electron in the bonding molecular orbital, 1 electron in the non-bonding molecular

orbital C) 1 electron in the bonding molecular orbital, 1 electron in the antibonding molecular

orbital D) 2 electrons in the non-bonding molecular orbital E) 2 electrons in the antibonding molecular orbital

Ans: A Topic: Atomic Orbitals, Electron Configuration, Hybridization

69. The following electron configuration represents:

1s 2sp32sp32sp32sp3

A) The ground state of nitrogen B) The ground state of oxygen C) The sp3 hybridized state of carbon D) The excited state of oxygen E) None of the above correctly identifies the given electron configuration

Ans: E Topic: Atomic Orbitals, Hybridization, Bonding

70. Identify the atomic orbitals involved in the C-2---C-3 sigma bond (indicated by an arrow) in the following molecule:

1

2

3

4

56

7A) sp2, sp2 B) sp2, sp C) sp2, sp3 D) sp3, sp2 E) sp, sp2

Ans: E

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Topic: Lewis Structures

71. In which of the following does the central atom have 2 pairs of non-bonding electrons? A) O3 B) CO2 C) CO3

2− D) NH4

+ E) H2S

Ans: E Topic: Molecular Geometry

72. Based on the VSEPR theory, which of the following would have a tetrahedral arrangement of electrons around the central atom?

A) BH3 B) NO2

− C) SiH4 D) CO3

2− E) SO3

Ans: C Topic: Molecular Geometry

73. What would be the spatial arrangement of the atoms of the ozone molecule (O3)? A) Linear B) Angular C) Trigonal planar D) Trigonal pyramidal E) Tetrahedral

Ans: B Topic: Periodic Trends, Electronegativity

74. Select the least electronegative element A) P B) N C) Mg D) Si E) K

Ans: E

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Topic: Atomic Orbitals, Hybridization

75. In which molecule(s) can the molecular geometry be attributed to an sp2 hybridized central atom?

A) PBr3 B) CH4 C) CHCl3 D) HNO2 E) None of the above has an sp2 hybridized central atom

Ans: D Topic: Bonding, Atomic Orbitals, Hybridization

76. Which molecule has the shortest carbon-carbon single bond?

I II III

IV V A) I B) II C) III D) IV E) V

Ans: E Topic: Atomic Orbitals, Hybridization 77. How many s-sp2 bonds are there in the following substance?

A) 2 B) 3 C) 4 D) 5 E) 12

Ans: B

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Topic: Atomic Orbitals, Hybridization

78. How many s-sp3 bonds are there in the following substance?

A) 3 B) 8 C) 12 D) 13 E) 16

Ans: D Topic: Resonance

79. Which of the following species exhibits resonance stabilization? A) H2SO4 B) O3 C) CO2 D) CCl4 E) None of the above species exhibit resonance

Ans: B SHORT ANS:WER QUESTIONS Topic: General

80. Organic compounds were originally defined as compounds obtained from __________. Ans: living sources/organisms

Topic: General

81. The modern definition of organic chemistry is _________________. Ans: the study of carbon compounds

Topic: General

82. Different compounds with the same molecular formula are referred to as __________. Ans: isomers

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Topic: General

83. Constitutional isomers differ in the _________________. Ans: connectivity of their atoms

Topic: General

84. The bond that results when two atoms share a pair of electrons is called a _________________.

Ans: covalent bond Topic: Atomic orbitals

85. Define an orbital. Ans: a region of space where the probability of finding an electron is high

Topic: Atomic orbitals

86.

An orbital is defined as a region of space where the probability of _________________ is high.

Ans: finding an electron Topic: Atomic orbitals

87. There are three fundamental rules that we use in writing electronic configurations for atoms and molecules. The configuration shown below (for oxygen) violates one of these rules. Which one?

1s 2p2p2p2sAns: Pauli exclusion principle

Topic: Molecular orbitals

88.

When atomic orbitals of opposite phase overlap a(n) _________________ molecular orbital is formed.

Ans: antibonding Topic: Molecular orbitals

89. When atomic orbitals of the same phase overlap a(n) _________________ molecular orbital is formed.

Ans: bonding

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Topic: Lewis Structures

90. Draw the Lewis structure of the nitrite ion, NO2

− , clearly indicating resonance contributors as well as non-bonding pairs of electrons and formal charges, as relevant.

Ans:

. .

..

N

O

O

..

. .

. .

..

. .

..

N

O

O

..

. .

. .

..

Topic: Isomers, Bond-Line Formulas

91. Draw all the isomers of C4H9Br, using bond-line formulas. Ans:

Br

Br

BrBr

Topic: Isomers, Bond-Line Formulas

92. Draw all the isomers of C4H10O, using bond-line formulas. Ans:

OH

OH

OO

OH

O

OH

Topic: Isomers, Bond-Line Formulas

93. Draw all isomers of C4H8, using bond-line formulas. Ans:

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Topic: Lewis Structures

94.

Draw the Lewis structure of acetic acid, CH3CO2H, clearly indicating all non-bonding pairs of electrons.

Ans:

CC

OH

O

HH

H. .

.. ..

. .

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MULTIPLE CHOICE QUESTIONS Topic: Intermolecular forces

1. Which compound would you expect to have the lowest boiling point? A) NH2

B) NH2

C)

N

H

D)

N

E)

NH2 Ans::

D

Topic: Molecular geometry, dipole moment

2. Which molecule would you expect to have no dipole moment (i.e., μ = 0 D)? A) CHF3 B)

F

H

H

F

C) :NF3 D)

H

F

H

F

E) CH2F2

Ans: B

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Topic: Intermolecular forces

3. Which of these compounds would have the highest boiling point? A) CH3OCH2CH2CH2OCH3 B) CH3CH2OCH2CH2OCH3 C) CH3CH2OCH2OCH2CH3 D) CH3OCH2CHOCH3

CH3 E) HOCH2CH2CH2CH2CH2OH

Ans: E Topic: Intermolecular forces

4. Which of these would you expect to have the lowest boiling point? A) CH3CH2CH2OH B) CH3CHCH3

OH C) CH3OCH2CH3 D) CH3CH2CH2CH2OH E) CH3CH2OCH2CH3

Ans: C Topic: Intermolecular forces

5. Which compound would have the highest boiling point? A) CH3CH2CH2CH2CH2CH3 B) CH3CH2OCH2CH2CH3 C) CH3CH2CH2CH2CH2OH D) CH3CH2OCH(CH3)2 E) CH3OCH2CH2CH2CH3

Ans: C Topic: Intermolecular forces

6. Which of the following is not found in the following substance? CH3CH2CH2CH2CH2OH

A) Ion-ion B) van der Waals C) Dipole-dipole D) Resonance E) Hydrogen bonding

Ans: D

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Topic: Intermolecular forces

7. Which compound would you expect to have the lowest boiling point? A)

NH2

O

B) H

N

O C)

N

O

D)

NH2

O E)

O NH

Ans: C Topic: Intermolecular forces

8. Which compound would you expect to have the highest boiling point? A) CH3OCH2CH2OCH3 B) CH3OCH2OCH2CH3 C) HOCH2CH2CH2CH2OH D) CH3OCH2CH2CH2OH E) (CH3O)2CHCH3

Ans: C Topic: Molecular geometry, dipole moment

9. Which of the following would have no net dipole moment (μ = 0 D)?

A) CBr4 B) cis-1,2-Dibromoethene C) trAns:-1,2-Dibromoethene D) 1,1-Dibromoethene E) More than one of these

Ans: E

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Topic: Molecular geometry, dipole moment

10. Which molecule has dipole moment greater than zero? A)

H

F

H

F

B)

H

H

F

F

C)

F

H

H

F

D) More than one of these E) None of these

Ans: D Topic: Intermolecular forces

11. The strongest of attractive forces is which type? A) van der Waals B) Ion-dipole C) Dipole-dipole D) Cation-anion E) Hydrogen bonds

Ans: D Topic: Intermolecular forces

12. Of the following compounds, the one with the highest boiling point is: A) CH3CH3 B) CH3CH2Cl C) CH3C=O

H D) CH3CH2OH E) CH3CH2OCH2CH3

Ans: D

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Topic: Intermolecular forces

13. This alkane is predicted to have the highest melting point of those shown: A) CH3CH2CH2CH3 B) CH3CHCH3

CH3 C) CH3CH2CH2CH2CH3 D) CH3CHCH2CH3

CH3 E)

CH3CCH3

CH3

CH3 Ans: E

Topic: Intermolecular forces

14. The solid alkane CH3(CH2)18CH3 is expected to exhibit the greatest solubility in which of the following solvents?

A) CCl4 B) CH3OH C) H2O D) CH3NH2 E) HOCH2CH2OH

Ans: A

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Topic: Intermolecular forces

15. Which compound would have the lowest boiling point?

OOH

OH

OH

OH

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: A Topic: Molecular geometry, Polarity

16. Which molecule(s) has dipole moment equal to zero? A) Cl

B) ClCl

C) Cl

Cl

D) Cl

Cl

Cl

E) None of these have dipole moment equal to zero Ans: C

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Topic: Molecular geometry, polarity

17. Which molecule has a zero dipole moment? A) SO2 B) CO2 C) CO D) CHCl3 E) None of these

Ans: B Topic: Molecular geometry, polarity

18. Which molecule has a zero dipole moment? A) CH3Cl B) CH2Cl2 C) CHCl3 D) CCl4 E) None of these

Ans: D Topic: Molecular geometry, polarity

19. Which molecule would have a dipole moment greater than zero? A) BeCl2 B) BCl3 C) CO2 D) H2O E) CCl4

Ans: D Topic: Molecular geometry, polarity

20. For a molecule to possess a dipole moment, the following condition is necessary but not sufficient.

A) Three or more atoms in the molecule B) Presence of one or more polar bonds C) A non-linear structure D) Presence of oxygen or fluorine E) Absence of a carbon-carbon double or triple bond

Ans: B

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Topic: Molecular geometry, polarity

21. A non-zero dipole moment is exhibited by: A) SO2 B) CO2 C) CCl4 D) BF3 E) Cl

Cl

Cl

Cl Ans: A

Topic: Intermolecular forces

22. Which of these is the weakest of the intermolecular attractive forces? A) Ion-ion B) van der Waals C) Dipole-dipole D) Covalent bonding E) Hydrogen bonding

Ans: B Topic: Functional groups

23. Which compound listed below is a secondary alcohol? A) CH3CHCH2CH3

OH B) CH3CHCH2OH

CH3 C)

CH3COH

CH3

CH3 D) CH3CH2CH2CH2OH E) CH3CH2CH2OCH3

Ans: A

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Topic: Functional groups

24. Which compound is a secondary amine? A) CH3CH2CH2NH2 B) CH3CHCH3

NH2 C)

CH3

CH3CH2NH

D) NH3C CH3

CH3 E) CH3CH2CHNH2

CH3 Ans: C

Topic: Functional groups

25. Which compound is an aldehyde?

NH

I II III

IV V

O O

O

O

OH

O

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Functional groups

26. Which compound is a ketone? A)

CH

OHO

B)

CH3CCH2CH3

O

C)

HCOCH3

O

D)

CH

HO

E)

CHH3C

OHH3C

Ans: B

Topic: Functional groups

27. Which compound is an ester?

NH

O

I II III

IV V

O

O

O

O

OH

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Functional groups

28. The compound shown below is a synthetic estrogen. It is marketed as an oral contraceptive under the name Enovid.

O

OH

In addition to an alkane (actually cycloalkane) skeleton, the Enovid molecule also contains the following functional groups:

A) Ether, alcohol, alkyne. B) Aldehyde, alkene, alkyne, alcohol. C) Alcohol, carboxylic acid, alkene, alkyne. D) Ketone, alkene, alcohol, alkyne. E) Amine, alkene, ether, alkyne.

Ans: D Topic: Functional Groups

29. Which is a 3° alkyl halide?

Cl

I II III

IV V

BrF

Br I

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Functional groups

30. Which is a 3° amine?

H2N

I II III

IV V

NH2NH

NNH2O

A) I B) II C) III D) IV E) V

Ans: D Topic: Functional groups

31. Which functional group is not contained in prostaglandin E1?

OH

OO

HOOHH H

H

H

Prostaglandin E1

A) Ketone B) 2° alcohol C) 3° alcohol D) Carboxylic acid E) Alkene

Ans: C

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Topic: Functional groups

32. The compound below is an adrenocortical hormone called cortisone. Which functional group is not present in cortisone?

O

OHO

OOH

A) 1° alcohol B) 2° alcohol C) 3° alcohol D) Ketone E) Alkene

Ans: B Topic: Functional groups

33. The compound shown below is a substance called Capsaicin, found in varying concentrations in several varieties of hot peppers, and responsible for their respective degrees of “heat”. Which functional groups are present in the molecule of capsaicin?

NH

OO

OH

CapsaicinA) Alkene, ketone, amine, alcohol, ester B) Alkene, ketone, alcohol, ether C) Alkene, amine, phenol, ether D) Ether, phenol, alkene, amide E) Ester, phenol, alkene, amide

Ans: D

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Topic: Functional groups

34. Drawn below is Atropine, found in Atropa belladonna, sometimes used in dilating pupils during an eye-exam. Which of the following functional groups is NOT in atropine?

N

O

O OH

Atropine

A) Amine B) Ester C) Alcohol D) Benzene Ring E) Ketone

Ans: E Topic: Functional groups

35. The compound shown below is the male sex hormone, testosterone.

O

OHO

In addition to a cycloalkane skeleton, testosterone also contains the following functional groups:

A) Alkene, ester, tertiary alcohol. B) Alkene, ether, secondary alcohol. C) Alkene, ketone, secondary alcohol. D) Alkyne, ketone, secondary alcohol. E) Alkene, ketone, tertiary alcohol.

Ans: C

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Topic: Functional groups

36. Which is a carboxylic acid?

O

O

OH

OH

I II III

IV V

OH

O O

O

O

O

A) I B) II C) III D) IV E) V

Ans: E Topic: Functional groups

37. Which compound is a tertiary alcohol?

H3CH2C HO

CH3

CH3

HO

O

OH

I II III

IV V

OH

A) I B) II C) III D) IV E) V

Ans: E

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Topic: Functional groups

38. Which compound is a primary amine with the formula C5H13N?

H2N

N

H2N

I II III

IV V

NH2

NH

A) I B) II C) III D) IV E) V

Ans: C Topic: Functional groups

39. Which compound can be classified as an ester as well as a ketone?

O

O O

O

O

O O

OO

OH

O

I II III

IV VOH

O

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Functional groups

40. The C–O–C bond angle in diethyl ether is predicted to be approximately: A) 90º B) 105º C) 110º D) 120º E) 180º

Ans: C Topic: Functional groups

41. Which compound(s) contain(s) tertiary carbon atom(s)?

F

BrOH

OH

I II III

IV VA) I, II, III B) I C) II, III D) I, IV E) V

Ans: D Topic: Isomers

42. The number of unique open-chain structures corresponding to the molecular formula C3H5Cl is:

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: C

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Topic: General, Bonding

43. The C4-C5 carbon-carbon bond in the following molecule results from the overlap of which orbitals ( in the order C4-C5) ?

1

23

45

67

o

A) sp–sp2 B) sp–sp3 C) sp2–sp2 D) sp2–sp3 E) sp3–sp2

Ans: E Topic: Functional groups

44. An example of a tertiary amine is:

NH2 H2N

NH2

HN

N

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: E

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Topic: Functional groups

45. Which functional groups are present in the following compound?

A) Alkene, 1º alcohol, ketone B) Alkene, 2º alcohol, aldehyde C) Alkene, 2º alcohol, ketone D) Alkyne, 1º alcohol, aldehyde E) Alkyne, 2º alcohol, ketone

Ans: B Topic: Functional groups, Isomerism

46. How many constitutional isomers are possible with the formula C4H10O? A) 3 B) 4 C) 5 D) 6 E) 7

Ans: E Topic: Functional groups

47. A tertiary carbon atom is present in which of these compounds?

OH

HO

ClCl

I II III

IV VA) I B) II, IV C) III, V D) IV E) All of these

Ans: C

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Topic: Functional groups

48. Which of these compounds is a secondary alkyl chloride? A) CH3CH2CH2CH2CH2Cl B)

CH3CCH2CH3

CH3

Cl C) CH3CHCH2CH2CH3

Cl D) CH3CH2CHCl

CH2CH3 E) Two of these

Ans: E Topic: Functional groups, Isomerism

49. How many 2º alkyl bromides, neglecting stereoisomers, exist with the formula C6H13Br?A) 4 B) 5 C) 6 D) 7 E) 8

Ans: C

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Topic: Functional Groups

50. Many organic compounds contain more than one functional group. Which of the following is both an aldehyde and an ether?

O

O

OO

O O

OO

OCH3

O

O

I II III

IV VA) I, B) II, IV C) V D) I, V E) III

Ans: A Topic: IR Spectroscopy

51. An oxygen-containing compound shows strong IR absorption at 1630-1780 cm-1 and 3200-3550 cm-1. What type of compound is it likely to be?

A) An alcohol B) A carboxylic acid C) An ether D) A ketone E) An aldehyde

Ans: B Topic: IR Spectroscopy

52. The absorption band for the O-H stretch in the IR spectrum of an alcohol is sharp and narrow in the case of:

A) a Nujol mull of the alcohol. B) a concentrated solution of the alcohol. C) a gas phase spectrum of the alcohol. D) the spectrum of the neat liquid E) none of these

Ans: C

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Topic: IR Spectroscopy

53. A split peak for the IR absorption due to bond stretching is observed for the carbonyl group in which of these compounds?

A) CH3CH2CH2COH

O

ca B)

CH3CH2CClO

C)

CH3CH2CNH2

O

D)

CH3CH2COCH2CH3

O

E)

CH3CH2COCCH2CH3

O O

Ans: E

Topic: IR Spectroscopy

54. The IR stretching frequency occurs at the lowest frequency for which of these bonds? A) C–H B) C–O C) C–Br D) C–N E) C–F

Ans: C Topic: IR Spectroscopy

55. The IR stretching frequency can be expected to occur at the lowest frequency for which of these bonds?

A) C–H B) O–H C) N–H D) S–H E) Difficult to predict

Ans: D

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Topic: IR Spectroscopy

56. The IR stretching frequency can be predicted to occur at the highest frequency for which of these bonds?

A) C–H B) C–F C) C–Cl D) C–Br E) C–I

Ans: A Topic: IR Spectroscopy

57. An anticipated IR absorption band may not be observed because: A) it occurs outside the range of the instrument used. B) no change occurs in the dipole moment during the vibration. C) the absorption band is eclipsed by another. D) the intensity is so weak that it cannot be differentiated from instrument noise. E) All of these

Ans: E Topic: IR Spectroscopy 58. IR evidence for the presence of the C=C would be most difficult to detect in the case of

which of these alkenes? A) B) C)

D)

E)

Ans: D

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Topic: IR Spectroscopy

59. The IR absorption due to the stretching of which of these carbon-hydrogen bonds occurs at the highest frequency?

I II III

IV V

HH H

H H

A) I B) II C) III D) IV E) V

Ans: E Topic: IR Spectroscopy

60. The IR spectrum of which type of compound will not show evidence of hydrogen bonding?

A) Aldehyde B) Alcohol C) Carboxylic acid D) Phenol E) Primary amine

Ans: A Topic: IR Spectroscopy

61. The IR spectrum of which type of compound generally exhibits evidence of hydrogen bonding?

A) Aldehyde B) Carboxylic acid C) Alkene D) Ester E) Ketone

Ans: B

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Topic: Intermolecular forces

62. The following substance is expected to have low solubility in which of the following solvent(s)?

O Na

OA) CCl4 B) C2H5OH C) CHCl3 D) CH2OHCH2CH2CH2CH2CH2OH E) The given substance is likely to be quite soluble in all of the solvents described

Ans: A Topic: IR Spectroscopy

63. The IR stretching frequency occurs at the lowest frequency for which of these bonds? A) B–H B) O-H C) N-H D) S-H E) Difficult to predict

Ans: D Topic: IR Spectroscopy

64. An oxygen-containing compound which shows sharp IR absorption at 2200 cm-1 and 3300 cm-1 is likely to be what type of compound?

A) An ester B) An alkene C) An alkyne D) An ether E) An aldehyde

Ans: B

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Topic: IR Spectroscopy

65. The IR spectrum of which of the following substances is likely to show a small, but sharp peak at 2200 cm-1?

OH

NH

O

I II III

IV VA) I B) II C) III D) IV E) V

Ans: E SHORT ANSWER QUESTIONS Topic: Functional Groups

66. Hydrocarbons containing carbon-carbon double bonds are referred to as ___________.

Ans: alkenes Topic: Functional Groups, IR Spectroscopy

67. An IR spectrum has significant peaks at 2200 and 3300 cm-1. What functional group is present in the molecule? Ans: A terminal alkyne

Topic: Functional Groups

68. A group in which a carbon atom has a double bond to an oxygen atom is called a __________. Ans: carbonyl

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Topic: Functional Groups, IR Spectroscopy

69. An IR spectrum has significant peaks at 3080 and 1650 cm-1. What functional group is present in the molecule?

Ans: an alkene Topic: Functional Groups, IR Spectroscopy

70. Examine the following IR spectrum, for substance P (C8H22O). Which oxygen containing functional group is present in P?

Ans: aldehyde

Topic: Functional Groups, IR Spectroscopy

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71. Examine the following IR spectrum, for substance P (C5H12O). Which oxygen containing functional group is present in P? Ans: alcohol

Topic: General

72. The six p-electrons in benzene are _____________ about the ring, which explains why all of the C-C bonds are the same length. Ans: delocalized

Topic: General

73. A polar covalent bond is one in which electrons are _____________. Ans: not shared equally

Topic: Functional Groups

74. Organic compounds are classified into chemical families on the basis of similarities in chemical properties; these similarities are primarily due to the presence of characteristic arrangements of atoms known as ________________. Ans: functional groups

Topic: Functional Groups

75. Unsaturated hydrocarbons may be distinguished from saturated hydrocarbons by the presence of one or more _____________. Ans: Pi bonds

Topic: Bonding, Solubility

76. Sodium chloride, which is quite soluble in water, is not very soluble in hexane. Why? Ans: Sodium chloride, which is an ionic substance, is soluble in a polar solvent such as

water, but not in a non-polar solvent such as hexane. Topic: Isomers, Functional Groups

77. Draw all tertiary amine isomers of C6H15N. Ans:

NN

N N N

N

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Topic: Isomers, Functional Groups

78. Draw all isomers of C6H14. Ans:

Topic: Isomers, Functional Groups

79. Draw a structural formula for C8H18 , in which there are two quaternary carbons. Ans:

Topic: Isomers, Functional Groups

80. Draw all isomers of C5H10O that are ketones. Ans: O O O

Topic: Isomers, Functional Groups

81. Draw all isomers of C3H8O and classify each according to functional group Ans:

C3H8O OHOH

Oprimary alcohol secondary alcohol ether

Topic: Isomers, Functional Groups

82. Draw all isomers of C6H12O that are aldehydes. Ans:

O O OO

O OO

Topic: Isomers, Functional Groups

83. Draw all isomers of C6H12O that are aldehydes and contain at least one tertiary carbon Ans:

O OOO

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Topic: IR Spectroscopy

84. The IR absorption frequencies of the C-H bond in alkanes, alkenes and alkynes are measurably different. Briefly explain why. Ans: IR absorption frequency depends on bond strength; the bond strength of C-H

bonds in alkanes, alkenes and alkynes is different because different atomic orbitals (hybridized) of carbon are involved in the bond: the C-H bond in alkanes is described as (sp3-s), that in alkenes is (sp2-s) and in alkynes, it is (sp-s). The relative % s v. % p character of the hybrid orbitals of carbon would indicate different bond lengths /bond strengths for alkanes, alkenes and alkynes, with the bond length / bond strength being the longest/weakest respectively. This results in different IR absorption frequencies.

Topic: Molecular Geometry, Dipole Moment

85. Carbon dioxide is non- polar, despite the fact that oxygen is much more electronegative than carbon. Briefly explain why, using relevant diagrams as appropriate to illustrate your Ans:wer. Ans: The overall dipole moment of a polyatomic molecule depends on two factors: the

polarity of various bonds and molecular geometry, since dipole forces have both magnitude and direction. In some molecules containing bonds of identical polarity, the molecular geometry may result in a net cancellation of the overall dipole forces. This is what happens in carbon dioxide: although there are two polar C-O bonds, because of the linear geometry of the molecule, the net dipole is zero. OCO

. .::. .

Topic: Intermolecular Forces

86. Ethanol, C2H5OH, and propane, C3H8, have approximately the same molar mass, yet, ethanol has a much higher boiling point. Briefly explain why. Ans: Strong hydrogen bonding between molecules of ethanol leads to elevation in

boiling point. No hydrogen bonding is possible between molecules of propane, resulting in a lower boiling point compared with ethanol.

Topic: Intermolecular Forces

87. Ethanol, C2H5OH, and dimethyl ether, CH3OCH3, have the same molar mass, yet, ethanol has a much higher boiling point. Briefly explain why. Ans: Strong hydrogen bonding between molecules of ethanol leads to elevation in

boiling point. No hydrogen bonding is possible between molecules of dimethyl ether, resulting in a lower boiling point compared with ethanol.

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Topic: IR Spectroscopy

88. IR absorption signals of alcohols are typically broad. However, IR spectra of gaseous samples show sharp peaks. Briefly explain why. Ans: Broad signals of alcohols are due to hydrogen bonding associated with the O-H

group. In gaseous samples, no hydrogen bonding is possible, and the signal becomes sharp.

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MULTIPLE CHOICE QUESTIONS Topic: Acid-Base Definitions

1. According to the Lewis definition, a base is a(n): A) Proton donor. B) Electron pair donor. C) Hydroxide ion donor.

D) Hydrogen ion donor. E) Electron pair acceptor. Ans: B Topic: Acid-Base Definitions

2. Which of the following is not both a Bronsted-Lowry acid and a Bronsted-Lowry base? A) HSO4

− B) H2PO4

− C) HCO3

− D) OH− E) SH−

Ans: D Topic: Acid-Base Definitions

3. Which of the following is not a conjugate acid - conjugate base pair (in that order)? A) H3PO4, H2PO4

− B) HBF4, BF4

− C) CH3CH2OH, CH3CH2O− D) H3O+, H2O E) HPO4

−, H2PO4−

Ans: E Topic: Acid-Base Definitions

4. The conjugate base of sulfuric acid is: A) H3SO4

+ B) SO3 C) HSO4

− D) H2SO3 E) HSO3

− Ans: C

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Topic: Acid-Base Definitions

5. Consider the equilibrium PO4

3− + H2O ⇄ ΗPΟ42− + ΟΗ−

Which are the Bronsted-Lowry bases? A) PO4

3− and HPO42−

B) PO43− and OH−

C) PO43− and H2O

D) H2O and OH−

E) H2O and HPO42−

Ans: B Topic: Acid-Base Definitions

6. Which of these is not a true statement? A) All Lewis bases are also Bronsted-Lowry bases. B) All Lewis acids contain hydrogen. C) All Bronsted-Lowry acids contain hydrogen. D) All Lewis acids are electron deficient. E) According to the Bronsted-Lowry theory, water is both an acid and a base.

Ans: B Topic: Acid-Base Definitions

7. For the equilibrium CH3NH3

+ + H2O ⇄ CH3NH3+ + H3O+

the two substances which both are acids are: A) H2O and H3O+ B) CH3NH3

+ and H2O C) CH3NH3

+ and CH3NH2 D) CH3NH3

+ and H3O+ E) CH3NH2 and H2O Ans: D

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Topic: Acid-Base Definitions

8. Which of the following is not a Lewis base? A) NH3

B) H− C) BF3 D) H2O E) H3C−

Ans: C Topic: Acid-Base Definitions

9. Which of the following is not a Bronsted-Lowry acid? A) H2O

B) (CH3)3N C) NH4

+ D) CH3CO2H E) HC≡CH

Ans: E Topic: Acid-Base Definitions

10. The reaction between which combination of substances below cannot be classified as a Bronsted-Lowry acid-base reaction? A) CH3Li + C2H5OH B) H2SO4 + CH3CO2Na C) BF3 + NH3 D) H3O+ + CH3NH- E) two of the above Ans: C

Topic: Acid-Base Definitions

11. Which of these is not a Lewis acid? A) AlCl3 B) H3O+ C) FeCl3 D) SO3 E) C4H10

Ans: E

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Topic: Acid-Base Definitions

12. This species is a carbon-based Lewis acid: A) CH4 B) HCCl3 C) CH3

+ D) :CH3

− E) ·CH3

Ans: C Topic: Acid-Base Definitions

13. What is the conjugate base of ethanol? A) CH3CH2O− B) CH3CH2

− C) CH3CH2OH2

+ D) CH3CH3 E) CH3OCH3

Ans: A Topic: Acid-Base Strength

14. Which of the acids below would have the strongest conjugate base? A) CH3CH2OH pKa = 18 B) CH3CO2H pKa = 4.75 C) ClCH2CO2H pKa = 2.81 D) Cl2CHCO2H pKa = 1.29 E) Cl3CCO2H pKa = 0.66 Ans: A

Topic: Acid-Base Definitions

15. Which of the following is a Lewis acid? A) H3O+

B) BF3 C) NF3 D) OH− E) N≡N

Ans: B

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Topic: Acid-Base Reactions

16. Adding sodium hydride to ethanol would produce: A) CH3CH2OCH2CH3 + H2 D) CH3CH2Na + NaOH B) CH3CH2OCH2CH3 + NaOH E) CH3CH3 + NaOH C) CH3CH2ONa + H2

D)CH3CH2Na + NaOH E) CH3CH3 + NaOH Ans: C Topic: Acid-Base Reactions

17. Adding sodium amide (NaNH2) to 1-butyne (CH3CH2C≡CH) would produce: A) CH3CH2C≡CNa + NH3 B) CH3CH2C≡C-C≡CH2CH3 + NaH + NH3 C) CH3CH2C≡CNH2 + NaH D) NaCH2CH2C≡CH + NH3 E) CH3CH(Na)C≡CH + NH3 Ans: A

Topic: Acid-Base Reactions

18. Which acid-base reaction would not take place as written? A) CH3Li + CH3CH2OH ⎯⎯⎯⎯→ CH4 + CH3CH2OLi B) HC≡CH + NaOH ⎯⎯⎯⎯→ HC≡CNa + H2O C) HC≡CNa + H2O ⎯⎯⎯⎯→ HC≡CH + NaOH D) CH3OH + NaH ⎯⎯⎯⎯→ CH3ONa + H2 E) CH3CO2H + CH3ONa ⎯⎯⎯⎯→ CH3CO2Na + CH3OH

Ans: E Topic: Acid-Base Reactions 19. Which acid-base reaction would not take place as written?

A) CH3Li + CH3CH2CH2CH2NH2 ⎯⎯⎯⎯→ CH4 + CH3CH2CH2CH2NHLi B) CH3C≡CH + NaOCH3 ⎯⎯⎯⎯→ HC≡CNa + CH3OH C) HC≡CNa + H2O ⎯⎯⎯⎯→ HC≡CH + NaOH D) CH3OH + NaNH2 ⎯⎯⎯⎯→ CH3ONa + NH3 E) CH3CO2H + CH3ONa ⎯⎯⎯⎯→ CH3CO2Na + CH3OH Ans: B

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Topic: Acid-Base Reactions

20. Which acid-base reaction would not take place as written? A) CH3Li + CH3CH2OH ⎯⎯⎯⎯→ CH4 + CH3CH2OLi B) H2C=CH2 + NaOH ⎯⎯⎯⎯→ H2C=CHNa + H2O C) CH3C≡CNa + H2O ⎯⎯⎯⎯→ CH3C≡CH + NaOH D) (CH3)2CHOH + NaH ⎯⎯⎯⎯→ (CH3)2CHONa + H2 E) CH3CO2H + CH3ONa ⎯⎯⎯⎯→ CH3CO2Na + CH3OH Ans: B

Topic: Acid-Base Reactions

21. The amide ion, NH2−, is a base which can be used only in which of the solvents shown

below: A) CH3OH B) CH3CH2OH C) H2O D) D2O E) Liquid NH3

Ans: E Topic: Acid-Base Reactions

22. Acetic acid dissociates most completely in: A) CCl4

B) Cl2C=CCl2 C) H2O D) (CH3CH2)2O E) the gas phase.

Ans: C Topic: Acid-base definitions, Acid-Base Reactions

23. Which pair of species are both bases in the following reaction? HCN and H2O ⇄ H3O+ and CN− A) H2O and CN− B) H3O+ and H2O C) HCN and H3O+

D) HCN and CN−

E) H3O+ and CN− Ans: A

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Topic: Acid-Base Reactions

24. What compounds are produced when sodium nitrate is added to a mixture of water and ethanol? A) HNO3 + NaOH B) HNO3 + CH3CH2ONa C) NaOH + CH3CH2ONa D) CH3CH2OCH2CH3 + NaOH E) No reaction occurs. Ans: E

Topic: Acid-Base Reactions

25. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaOH (aq) + CH3CH2CH2CO2H B) CH3CH2ONa in ethanol + ethene C) CH3Li in hexane + ethyne

D) NaNH2 in liq. NH3 + ethanol E) NaC2H3O2 (aq) + HI Ans: B Topic: Acid-Base Reactions

26. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaNH2 + CH3CH2CH2CH2CH2CH3 B) CH3CH2CO2Na + HI C) CH3Li in hexane + ethyne D) NaH + methanol E) Two of the above will not occur

Ans: A Topic: Acid-Base Reactions

27. Which reaction of these potential acids and bases does not occur to any appreciable degree due to an unfavorable equilibrium? A) NaNH2 + CH3CH2CH2CH2CH2OH B) CH3CH2CO2H + NaCl C) NaHCO3 + CH3CH2CO2H D) NaH + CH3CH2CH2CH2CH2NH2 E) all of the above will occur due to a favorable equilibrium Ans: E

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Topic: Acid-Base Reactions

28. Which combination of reagents is the least effective in generating sodium ethoxide, CH3CH2ONa? A) CH3CH2OH + NaH B) CH3CH2OH + NaNH2 C) CH3CH2OH + NaOH D) CH3CH2OH + CH3Li E) CH3CH2OH + HC≡CNa Ans: C

Topic: Acid-Base Reactions

29. Which combination of reagents is effective in generating sodium ethoxide, CH3CH2ONa?

A) CH3CH2OH + KH B) CH3CH2OH + NaNH2 C) CH3CH2OH + Na D) Two of the above E) All of the above Ans: E Topic: Acid-Base Reactions

30. Which combination of reagents is effective in generating sodium propynide, CH3C≡CNa?

A) CH3C≡CH + KH B) CH3C≡CH + (CH3)2CHONa C) CH3C≡CH + C2H5Li D) Two of the above E) All of the above Ans: B Topic: Acid-Base Reactions, base strength

31. In the reaction, Na+NH2− + CH3OH ⎯⎯⎯⎯→ CH3O−Na+ + NH3, the stronger

base is: A) NaNH2 B) CH3OH C) CH3ONa

D) NH3 E) This is not an acid-base reaction. Ans: A

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Topic: Acid-Base Reactions, isotope labeling

32. Which sequence is the best one to use to prepare CH3C≡CD? A) CH3C CH NaH D2O

B) CH3C CH NaOH D2O

C)

CH3C CHCH3ONa D2O

D) CH3C CH DOH

E) None of these will be successful. Ans: A Topic: Acid-Base Reactions

33. Adding sodium hydride, NaH, to water produces: A) H2 and NaOH(aq) B) H-(aq) + Na+(aq) C) H3O+(aq) + Na+(aq)

D) H3O−(aq) + Na+(aq) E) Na2O + H2

Ans: A Topic: Acid-Base Reactions

34. Adding methyllithium , CH3Li, to ethanol produces: A) CH3CH2Li + CH3OH B) CH3CH2OLi + CH4 C) CH3CH2OCH3 + LiH D) All of the above E) No reaction takes place

Ans: A Topic: Acid-Base Reactions, isotope labeling

35. Which reaction will yield CH3CH2-D? A) CH3CH3 + D2O B) CH3CH2Li + D2O C) CH3CH2OLi + D2O

D) CH3CH2OH + D2O E) More than one of these Ans: B

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Topic: Acid-Base Reactions, isotope labeling

36. A product of the reaction, CH3CH2Li + D2O ⎯⎯⎯⎯→ is A) CH3CH2OD B) CH3CH2CH2CH3 C) CH2=CH2

D) CH3CH2D E) CH3CH2OCH2CH3

Ans: D Topic: Relative acid strength

37. The compounds ethane, ethene, and ethyne exhibit this order of increasing acidity: A) Ethyne < ethene < ethane B) Ethene < ethyne < ethane C) Ethane < ethyne < ethene

D) Ethane < ethene < ethyne E) Ethene < ethane < ethyne Ans: D Topic: Relative acid/base strength

38. Which is an incorrect statement? A) RSH compounds are stronger acids than ROH compounds. B) PH3 is a weaker base than NH3. C) NH2

− is a stronger base than OH−. D) OH− is a stronger base than OR−. E) H− is a stronger base than OR−.

Ans: D Topic: Relative acid/base strength

39. The correct sequence of the ions shown, in order of increasing basicity, is: A) CH3CH2:− < CH2=CH:− < HC≡C:− B) CH3CH2:− < HC≡C:− < CH2=CH:− C) HC≡C:− < CH3CH2:− < CH2=CH:−

D) CH2=CH:− < HC≡C:− < CH3CH2:−

E) HC≡C:− < CH2=CH:− < CH3CH2:− Ans: E

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Topic: Solvent effects

40. Which is a protic solvent? A) CCl4 B) HCCl3 C) CH3OH D) CH3(CH2)4CH3 E) CH3CH2OCH2CH3 Ans: C

Topic: Solvent effects

41. Which might be used as protic solvent? A)

O

O

B)

H2N C)

N

O

D)

O E) O

Ans: B

Topic: Solvent effects

42. Which of the following classes of substances cannot be used as protic solvents? A) esters B) aldehydes C) ketones D) carboxylic acids E) two of the above Ans: D

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Topic: Acid constants

43. If a 0.01 M solution of a weak acid has a pH of 4.0, the pKa of the acid is: A) 10.0

B) 8.0 C) 6.0 D) 4.0 E) 2.0 Ans: C

Topic: General

44. Which one of the following is a true statement? A) The stronger the acid, the larger is its pKa. B) The conjugate base of a strong acid is a strong base. C) Acid-base reactions always favor the formation of the stronger acid and the stronger

base. D) Strong acids can have negative pKa values. E) Hydrogen need not be present in the molecular formula of a Bronsted-Lowry acid.

Ans: D Topic: Relative acid/base strengths

45. The basic species are arranged in decreasing order of basicity in the sequence: A) F− > OCH3

− > NH2− > CH3CH2

− B) OCH3

− > CH3CH2− > NH2

− > F− C) CH3CH2

− > NH2− > OCH3

− > F− D) NH2

− > CH3CH2− > F− > OCH3

− E) NH2

− > OCH3− > CH3CH2

− > F− Ans: C Topic: pKa calculations

46. A particular acid has Ka = 2.0 x 10-5 (in aqueous solution). The evaluation of which of these expressions gives the value for pKa? A) 10-14/2.0 x 10-5 B) 10-14(2.0 x 10-5) C) 5 – log 2.0 D) -5 + log 2.0 E) 2.0 x 10-5/10-14

Ans: C

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Topic: Solvent effects

47. As a consequence of the "leveling effect," the strongest acid which can exist in appreciable concentration in aqueous solution is:

A) H3O+ B) H2SO4 C) HClO4 D) HCl E) HNO3 Ans: A

Topic: Relative acid/base strengths

48. Based on the position of the central atom in the periodic chart, we predict that the strongest acid of the following is:

A) H2O B) H2S C) H2Se D) H2Te Ans: D

Topic: Acid dissociation, thermodynamic calculations

49. An acid, HA, has the following thermodynamic values for its dissociation in water at 27º C: ΔH = -8.0 kJ mol-1; ΔS = -70 kJ K-1mol-1. The ΔG for the process is: A) +29 kJ mol-1 B) +13 kJ mol-1 C) -6.1 kJ mol-1

D) -13 kJ mol-1 E) -29 kJ mol-1 Ans: B Topic: Relative acid/base strengths, solvent effects

50. Which of these bases is the strongest one which can be used (and retains its basic character) in aqueous solution?

A) OCH3−

B) F− C) OH− D) C2H3O2

− E) HSO4

Ans: C

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Topic: Acidity constant- thermodynamic principles

51. The acidity constant, Ka, differs from the equilibrium constant, Keq, for the dissociation of the same acid in water at the same temperature and concentration in what way? A) Ka can be determined experimentally with less accuracy than Keq. B) The two terms are identical numerically. C) Ka is used for strong acids only; Keq for weak acids. D) Ka is the reciprocal of Keq. E) Keq = Ka/[H2O].

Ans: E Topic: Acids/bases-general principles

52. Which of the following is an untrue statement? A) The % dissociation of a weak acid increases with increasing dilution of the acid

solution. B) The stronger an acid, the weaker its conjugate base. C) The larger the value of Ka for an acid, the smaller the value of its pKa. D) Comparison of the acidity of strong acids in solution requires the use of a solvent

less basic than water. E) The stronger the acid, the more positive the value of ΔGº for the dissociation.

Ans: E Topic: Acid-base reactions

53. When proton transfer reactions reach equilibrium, there have been formed: A) the weaker acid and the weaker base. B) the weaker acid and the stronger base. C) the stronger acid and the weaker base. D) the stronger acid and the stronger base. E) All proton transfers go to completion; they are not equilibrium processes.

Ans: A Topic: Relative acid-base strengths

54. For the simple hydrides, MHn, pKa values decrease in the order: A) CH4 > NH3 > H2O > H2S > HBr B) HBr > H2S > H2O > NH3 > CH4 C) HBr > H2O > NH3 > H2S > CH4

D) NH3 > H2S > CH4 > H2O > HBr E) H2S > H2O > HBr > NH3 > CH4

Ans: A

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Topic: Relative acid-base strengths, solvent effects

55. The compound aniline, C6H5NH2, has weakly basic properties in aqueous solution. In this other solvent, aniline would behave as a strong base. A) CH3OH B) CH3CH2OH C) CF3CO2H

D) Liquid NH3 E) CH3(CH2)4CH3 Ans: C Topic: Relative acid-base strengths

56. Which of the following organic compounds is the strongest acid? A) C6H12 pKa = 52 B) CH3CH3 pKa = 50 C) CH3CH2OH pKa = 18

D) CH3CO2H pKa = 5 E) CF3CO2H pKa = 0 Ans: E Topic: Relative acid-base strengths

57. Which is the strongest acid? A) CH3CH2OH B) CH3CO2H C) HC≡CH D) CH2=CH2 E) CH3CH3 Ans: B

Topic: Relative acid-base strengths

58. Which is the strongest acid? A) CH2ClCH2CH2CH2CH2CO2H B) CH3CHBrCH2CH2CH2CO2H C) CH3CH2CH2CBr2CH2CO2H D) CH3CH2CH2CHFCH2CO2H E) CH3CH2CH2CF2CH2CO2H

Ans: E

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Topic: Relative acid-base strengths

59. Which is the strongest acid? A) CH3CH2CH2CH2CHFCO2H B) CH3CHBrCH2CH2CH2CO2H C) CH3CH2CH2CHClCH2CO2H D) CH3CH2CH2CHFCH2CO2H E) CH3CH2CH2CHICH2CO2H

Ans: A Topic: Relative acid-base strengths

60. Which is the weakest acid? A) CH3CH2CH2CH2CHFCO2H B) CH3CHCH2CH2CH2CH2OH C) CH3CH2CH2CH2CH2SO3H D) CH3CH2CH2CH2CH=CH2 E) CH3CH2CH2CH2NH2

Ans: A Topic: Relative acid-base strengths

61. Which of the following substances has a hydrogen atom with pKa ≈25? A) CH3CH2CH2CH2CO2H B) CH3CHCH2C≡CCH3 C) CH3CH2CH2C≡CH D) CH3CH2CH2CH2CH=CH2 E) CH3CH2CH2CH2NH2

Ans: C

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Topic: Relative acid-base strengths

62. Hydrogen atom(s) from which position(s) is (are) most likely to be abstracted when the following substance is treated with NaH?

12

34

8

56

7

910

A) 1 B) 1, 5, 6 C) 1, 2 D) 3, 4, 7, 8, 9, 10 E) Hydrogens from all of the positions are equally likely to be abstracted by NaH.

Ans: A Topic: Relative acid-base strengths

63. Which of the following correctly lists the compounds in order of decreasing acidity? A) H2O > HC≡CH > NH3 > CH3CH3 B) HC≡CH > H2O > NH3 > CH3CH3 C) CH3CH3 > HC≡CH > NH3 > H2O

D) CH3CH3 > HC≡CH > H2O > NH3 E) H2O > NH3 > HC≡CH > CH3CH3

Ans: A Topic: Relative acid-base strengths

64. Select the strongest base. A) OH− B) RC≡C− C) NH2

− D) CH2=CH− E) CH3CH2

Ans: E

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Topic: Relative acid-base strengths

65. A group of acids arranged in order of decreasing acidity is: HNO3 > CH3COOH > C6H5OH > H2O > HC≡CH What is the arrangement of the conjugate bases of these compounds in decreasing order of basicity? A) NO3

− > CH3COO− > C6H5O− > OH− > HC≡C− B) CH3COO− > C6H5O− > NO3

− > OH− > HC≡C− C) C6H5O− > NO3

− > HC≡C− > OH− > CH3COO− D) HC≡C− > OH− > C6H5O− > CH3COO− > NO3

− E) No prediction of relative base strength is possible.

Ans: D Topic: Relative acid-base strengths

66. What prediction can be made of the relative strengths of the conjugate bases of: H2S, HCl, SiH4, PH3? A) PH2

− > SiH3− > HS− > Cl−

B) SiH3− > PH2

− > HS− > Cl− C) Cl− > HS− > PH2

− > SiH3−

D) HS− > Cl− > SiH3− > PH2

− E) Cl− > PH2

− > SiH3− > HS−

Ans: B Topic: Acids/bases- general

67. Which of these species is not amphoteric? A) HC≡C−

B) HS− C) NH3 D) CH3

− E) HPO4

Αns: D

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Topic: Acids/bases- general

68. Which of these phosphorus-based acids is dibasic? A)

P

O

OH

OHHO

B)

P

O

H

OHHO

C)

P

O

OH

HH

D)

P

O

OH

OHO P

O

OH

OH E)

P

O

OH

PHO

O

OH

OH

Ans: B Topic: Acids/bases- general

69. Why cannot one determine the relative acid strengths of HClO4 and HNO3 using aqueous solutions of these acids? A) The acids are insufficiently soluble for the measurements. B) A more basic solvent than H2O must be used. C) H2O is too basic a solvent for the distinction to be made. D) These oxidizing acids cause redox reactions to occur. E) Actually, the acid strengths can be determined using aqueous solutions.

Ans: C Topic: Acids/bases- general

70. Which of these is not a diprotic acid? A) H2S B) H2SO4 C) H2O D) (COOH)2 E) H2PO4

- Ans: C

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Topic: Acids/bases- thermodynamic principles

71. Which set contains non-equivalent members? A) Enthalpy and heat content B) Endothermic reaction and +ΔH C) Exothermic reaction and -ΔH

D) Kinetic energy and energy of motion E) High energy and high stability Ans: E SHORT-ANSWER QUESTIONS: Topic: General Reactivity

72. Addition reactions are characteristic of compounds with ______________. Ans: multiple bonds Topic: Reaction Types

73. The four basic types of reactions are: ________________. Ans: substitution, addition, elimination, rearrangement Topic: Reaction Mechanisms

74. The process of bond-breaking where each fragment takes away one of the electrons from the bond is called ____________.

Ans: homolysis Topic: Reaction Mechanisms

75. Heterolytic bond-breaking produces __________. Ans: charged fragments/ions Topic: Acids and Bases

76. According to Bronsted-Lowry theory, an acid is a substance that can ____________. Ans: donate a proton Topic: Acids and Bases

77. According to Lewis theory, a base is a substance that can _________. Ans: donate a lone pair of electrons

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Topic: Acids and Bases

78. The molecule or ion that is formed when an acid loses its proton is called the ______________.

Ans: conjugate base Topic: Nucleophiles and Electrophiles

79. Reagents that seek to react with a proton or some other electron-deficient center are called ____________.

Ans: nucleophiles Topic: Acids and Bases

80. A substance that can donate a lone pair of electrons is a ____________ according to ____________ theory.

Ans: base; Lewis Topic: Curved Arrow Notation

81. When drawing mechanisms, chemists generally use curved arrows. The curved arrow begins with ______________ and points toward ______________.

Ans: a lone pair or covalent bond; a site of electron deficiency Topic: Acids and Bases

82. Why do water-insoluble carboxylic acids dissolve in aqueous sodium hydroxide? Ans: Because they are converted to water-soluble salts. Topic: Relative Acidity

83. Bond polarization that takes place through space and through the bonds of the molecule is called the _____________.

Ans: inductive effect Topic: Energy

84. What are the two fundamental types of energy? Ans: potential energy and kinetic energy Topic: Types of Solvents

85. Define a protic solvent. Ans: one that has a hydrogen atom attached to a strongly electronegative element such as oxygen

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Topic: Relative acid strength

86. Briefly, but clearly, explain why the –OH hydrogen in acetic acid (CH3CO2H) is more acidic than in ethanol (C2H5OH).

Ans: The greater acidity of the –OH hydrogen in acetic acid is due primarily to two factors: resonance and inductive effects. In acetic acid, the presence of the neighboring carbonyl group has an electron-withdrawing inductive effect on the –OH hydrogen, increasing its acidity relative to ethanol, in which there is no carbonyl group. Also, comparison of the respective conjugate bases shows that, unlike the ethoxide ion, the acetate ion is stabilized by resonance. This too, is reflected in the greater acid strength of the corresponding acid species.

OH

O

OH

O

O

O

O

O(- H+)

(- H+)

Inductive effect: electron withdrawing resonance stabilized anion

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Topic: Relative acid strength, isotope labeling

87. Isotope labeling is an important tool in the study of reaction mechanisms. How will you selectively deuterate the specified hydrogen atom, indicated by an arrow, in the following compound? Use equations to clarify your answer and briefly explain your rationale.

H

Ans: The specified hydrogen is attached to an sp-hybridized carbon and is thus more acidic than all the other hydrogens in the molecule. By using an appropriate strong base, such as NaH or NaNH2, the acetylenic hydrogen is selectively removed; adding D2O then replaces the lost hydrogen atom with a deuterium atom.

Hi) NaH or NaNH2

D

ii) D2O

Topic: Acid-base reactions

88. Write an equation to show the reaction between ethanol, C2H5OH and methyllithium, CH3Li. Draw all non-bonding electrons and show electron flow with curved arrows.

Ans: O

HCH3 Li+ O Li+ CH4+

....

: +....:

Topic: Acid-base reactions, solvent selection

89. You are planning to carry out a reaction between propyne, CH3C≡CH and sodium amide, NaNH2. You also need to choose an appropriate solvent for carrying out the reaction. Would ethanol be suitable for this purpose? Explain your rationale clearly.

Ans: No, ethanol would be unsuitable for carrying out the reaction between propyne and methyllithium. The pKa of ethanol is ~16, and sodium amide is strong enough a base to readily abstract a proton from the solvent ( pKa of NH3 is ~38); in doing so, it becomes deactivated and is no longer available to react with propyne (pKa ~25). Typically, the selected solvent should be chemically inert toward all substances used in the reaction, so that it does not interfere with the desired reaction.

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Topic: Acid-base reactions, solvent selection

90. You are planning to purify an impure sample of benzoic acid, known to be contaminated with naphthalene. Propose a strategy for purifying this sample, making use of acid-base principles, using equations to further clarify your answer.

Ans: Benzoic acid reacts with aqueous NaOH to form a water soluble salt, while naphthalene, which is not soluble in water to any appreciable extent, does not react with NaOH. So, upon shaking the impure sample with NaOH (aq), the naphthalene remains as a solid, while the benzoic acid dissolves in the aqueous medium as sodium benzoate. After filtration, HCl is added to the filtrate to regenerate benzoic acid, which precipitates as almost pure crystals. Cooling maximizes the yield of the purified product, after which pure crystals can be obtained by filtration.

Alternatively, before beginning the reaction with aqueous NaOH, the impure sample is first dissolved in diethyl ether (benzoic acid and naphthalene are both soluble in ether) and placed in a separatory funnel. After shaking thoroughly with aqueous NaOH, the aqueous layer (which now contains sodium benzoate) is collected. The rest of the procedure is as described earlier.

OH

ONaOH

OH

ONaOH

X

ONa

OHCl OH

O

No reaction

water soluble

water insoluble

water insoluble water insolublePURE

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MULTIPLE CHOICE QUESTIONS Topic: Nomenclature

1.

The IUPAC name for is: A) 6-Ethyl-3,4-dimethylheptane B) 2-Ethyl-4,5-dimethylheptane C) 3,4,6-Trimethyloctane D) 3,5,6-Trimethyloctane E) 2-(1-Methylpropyl)-4-methylhexane

Ans: C Topic: Nomenclature

2.

An IUPAC name for is: A) 5-Methyl-4-(1-methylpropyl)hexane B) 2-Methyl-3-(1-methylpropyl)hexane C) 2-Methyl-3-(2-methylpropyl)hexane D) 3-Methyl-4-(1-methylethyl)heptane E) 5-Methyl-4-(1-methylethyl)heptane

Ans: D Topic: Nomenclature

3. A correct IUPAC name for the following compound is:

A) 2,5-Dimethyl-3-propylheptane B) 3,6-Dimethyl-5-propylheptane C) 6-Methyl-4-(1-methylethyl)octane D) 2-Methyl-3-(2-methylbutyl)hexane E) 3-Methyl-5-(1-methylethyl)octane

Ans: E

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Topic: Nomenclature

4. A correct IUPAC name for the following compound is:

OH Cl A) 4-propyl-5-chloro-3-heptanol B) 4-propyl-3-chloro-5-heptanol C) 4-(1-chloropropyl)-3-heptanol D) 5-chloro-4-propyl-3-heptanol E) 3-hydroxy-4-propyl-5-chloroheptane Ans: D

Topic: Nomenclature

5. Which of the following pairs of compounds represent pairs of constitutional isomers? A) 2-Methylbutane and pentane B) 2-Chlorohexane and 3-chlorohexane C) sec-Butyl bromide and tert-butyl bromide D) Propyl chloride and isopropyl chloride E) All of the above

Ans: E

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Topic: Nomenclature

6. Which of the following is bicyclo[3.2.2]nonane?

I II III

IV VA) I B) II C) III D) IV E) V

Ans: C Topic: Nomenclature

7. Select the systematic name for HCl

H Cl A) cis-1,3-Dichlorocyclopentane B) trans-1,4-Dichlorocyclopentane C) cis-1,2-Dichlorocyclopentane D) trans-1,3-Dichlorocyclopentane E) 1,1-Dichlorocyclopentane

Ans: D

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Topic: Nomenclature

8. Which compound is a bicycloheptane?

I II III

IV VA) I B) II C) III D) IV E) V

Ans: D Topic: Nomenclature

9. Which isomer of C5H10 would you expect to have the smallest heat of combustion? A) Cyclopentane B) Methylcyclobutane C) 1,1-Dimethylcyclopropane D) cis-1,2-Dimethylcyclopropane E) trans-1,2-Dimethylcyclopropane

Ans: A Topic: Nomenclature

10. Which is the correct name for the compound shown below?

A) Bicyclo[2.2.0]hexane B) Bicyclo[2.2.0]butane C) Bicyclo[2.2.2]hexane D) Bicyclo[2.2.1]hexane E) Disquarane

Ans: A

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11. What is the name of this compound?

A) Bicyclo[2.2.2]octane B) Bicyclo[3.2.1]octane C) Bicyclo[4.1.1]octane D) Bicyclo[4.2.0]octane E) Bicyclo[3.3.0]octane

Ans: D Topic: Nomenclature

12. What is the common name for this compound?

Br

A) Isobutyl bromide B) tert-Butyl bromide C) Butyl bromide D) sec-Butyl bromide E) Bromo-sec-butane

Ans: A Topic: Nomenclature

13. A correct IUPAC name for the following compound is: Br

A) 3,6,7-trimethyl-4-bromo-1-octene B) 4-bromo-3-methyl-6-isopropyl-1-heptene C) 4-bromo-3,6,7-trimethyl-1-octene D) 4-bromo-6-isopropyl-3-methyl-1-heptene E) 4-bromo-6-isopropyl-3,6-dimethyl-1-hexene Ans: C

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14. A correct name for the following compound is:

A) 2-Methylbicyclo[4.3.0]nonane B) 1-Methylbicyclo[4.3.1]nonane C) 7-Methylbicyclo[4.3.0]nonane D) 2-Methylbicyclo[4.3.1]nonane E) 1-Methylbicyclo[4.3.0]nonane

Ans: A Topic: Nomenclature Use the following to answer questions 15-17:

I II III

IV V

15. Which of the above is bicyclo[3.3.1]nonane? A) I B) II C) III D) IV E) V

Ans: D Topic: Nomenclature

16. Which of the above is bicyclo[5.2.0]nonane? A) I B) II C) III D) IV E) V

Ans: E

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17. Which of the above is bicyclo[4.3.0]nonane? A) I B) II C) III D) IV E) V

Ans: A Topic: Nomenclature Use the following to answer questions 18-19:

Br

H

Br

H

H

Br

Br

H

Br

H

H

Br

I II III Topic: Nomenclature

18. trans-1,2-Dibromocyclohexane is represented by structure(s): A) I B) II C) III D) II and III E) I and II

Ans: D Topic: Nomenclature

19. cis-1,2-Dibromocyclohexane is represented by structure(s): A) I B) II C) III D) II and III E) I and II

Ans: A

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20. cis-1,3-Dibromocyclohexane is represented by structure(s):

Br

H H

Br

Br

HH

Br

H

BrH

Br

I II IIIA) I B) II C) III D) II and III E) I and II

Ans: A Topic: Nomenclature

21.

An IUPAC name for the group

CH3CHCH2−CH2CH3 is:

A) Isopentyl B) Isoamyl C) sec-Butylmethyl D) 2-Methylbutyl E) 2-Ethylpropyl

Ans: D Topic: Nomenclature

22. The neopentyl group has the alternative name: A) 1,1-Dimethylpropyl B) 1,2-Dimethylpropyl C) 2,2-Dimethylpropyl D) 1-Methylbutyl E) 2-Methylbutyl

Ans: C

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23.

The correct IUPAC name for Cl

Br

is: A) 2-Bromo-4-chloro-4-isopropylpentane B) 4-Bromo-2-chloro-2-isopropylpentane C) 5-Bromo-3-chloro-2,3-dimethylhexane D) 2-Bromo-4-chloro-4,5-dimethylhexane E) 2-(2-Bromopropyl)-2-chloro-3-methylbutane

Ans: C Topic: Nomenclature

24. Which of the following is a correct name which corresponds to the common name tert-pentyl alcohol?

A) 2,2-Dimethyl-1-propanol B) 2-Ethyl-2-propanol C) 2-Methyl-2-butanol D) 3-Methyl-1-butanol E) Methyl tert-butanol

Ans: C Topic: Nomenclature

25. The correct IUPAC name for the following compound is:

OH

A) 1-Hydroxy-3-sec-butylcyclopentane B) 3-sec-Butyl-1-cyclopentanol C) 1-sec-Butyl-3-cyclopentanol D) 4-sec-Butyl-1-cyclopentanol E) 3-Isobutyl-1-cyclopentanol

Ans: B

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26. What is a correct name for the following compound?

A) 3-Isobutyl-2-methylheptane B) 3-sec-Butyl-2-methyloctane C) 5-Isobutyl-6-methylheptane D) 2-Ethyl-3-isopropyloctane E) 4-Isopropyl-3-methylnonane

Ans: E Topic: Nomenclature

27. What is the correct name of the following compound?

Cl

A) 1-Chlorobicyclo[4.1.1]octane B) 2-Chlorobicyclo[4.1.0]octane C) 2-Chlorobicyclo[4.1.1]octane D) 2-Chlorobicyclo[4.1.1]heptane E) 5-Chlorobicyclo[4.1.1]octane

Ans: C Topic: Nomenclature

28. What is the correct IUPAC name for the following compound?

HO A) 3-Hydroxymethylheptane B) 3-Hydroxymethylhexane C) 3-Methyloxyheptane D) 2-Ethyl-1-hexanol E) 2-Ethyl-1-heptanol

Ans: D

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29. Which of the following structures represents bicyclo[3.2.1]octane?

I II III

IV VA) I B) II C) III D) IV E) V

Ans: E Topic: Nomenclature

30. Which of these is the common name for the 1,1-dimethylpropyl group? A) tert-Butyl B) tert-Pentyl C) Isopentyl D) Neopentyl E) sec-Pentyl

Ans: B Topic: Nomenclature

31. Neglecting stereochemistry, which of these common group names is ambiguous, i.e., does not refer to one specific group?

A) Butyl B) sec-Butyl C) tert-Pentyl D) Neopentyl E) sec-Pentyl

Ans: E

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32. What is the correct IUPAC name for the following compound? OH

A) 5-Ethyl-3-methylhexanol B) 5-Ethyl-3-methyl-1-hexanol C) 2-Ethyl-4-methyl-6-hexanol D) 3,5-Dimethyl-7-heptanol E) 3,5-Dimethyl-1-heptanol

Ans: E Topic: Nomenclature

33. Isopentyl is the common name for which alkyl group? A) CH3CH2CH2CH

CH3 B) CH3CH2CHCH2

CH3 C) CH3CHCH2CH2

CH3 D) CH3CH2CH

CH2CH3 E)

CH3CCH2

CH3

CH3 Ans: C

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34.

An IUPAC name for is: A) 3-Isobutyl-2,4-dimethylhexane B) 3-sec-Butyl-2,5-dimethylhexane C) 4-sec-Butyl-2,5-dimethylhexane D) 4-Isopropyl-2,5-dimethylheptane E) 4-Isopropyl-3,6-dimethylheptane

Ans: D Topic: Nomenclature

35. An IUPAC name for the following compound is:

A) 4-Isobutyl-3,4-dimethylheptane B) 4-sec-Butyl-2,4-dimethylheptane C) 2,4,5-Trimethyl-4-propylheptane D) 3,4,6-Trimethyl-4-propylheptane E) 4-Isobutyl-4,5-dimethylheptane

Ans: C Topic: Nomenclature

36. What is the correct IUPAC name for the following compound?

HO A) 3-Hydroxymethyl-2-heptene B) 2-(1-methylethyl)-4-hexen-1-ol C) 5-(1-methylethyl)-2-hexen-6-ol D) 5-isopropyl-2,6-hexenol E) 2-(1-methylethyl)-4-hepten-1-ol

Ans: B

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37. What is the correct IUPAC name for the following compound? OH

F A) 5-Ethyl-3-fluorohexanol B) 5-Ethyl-3-fluoro-1-hexanol C) 2-Ethyl-4-fluoro-6-hexanol D) 3-fluoro-5-methyl-7-heptanol E) 3-fluoro-5-methyl-1-heptanol

Ans: E Topic: Nomenclature

38. A correct name for the following compound is:

Cl A) 3-chloro-8-methylbicyclo[4.3.0]nonane B) 8-Methyl-3-chlorobicyclo[4.3.1]nonane C) 3-Methyl-7-chlorobicyclo[4.3.0]nonane D) 3-Methyl-7-chlorobicyclo[4.3.1]decane E) 3-chloro-8-methyl[4.3.0]bicyclononane

Ans: A Topic: Nomenclature

39. A correct name for the following compound is:

Br

A) 4-bromo-3,8-dimethylbicyclo[5.2.2]nonane B) 3,8-dimethyl-4-bromo-bicyclo[5.2.0]nonane C) 4-bromo-3,8-dimethylbicyclo[5.2.1]decane D) 7-bromo-2,6-dimethylbicyclo[5.2.0]nonane E) 4-bromo-3,8-dimethylbicyclo[5.2.0]nonane

Ans: E

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40. The least stable conformation of butane is:

HH3C

H

H

HH3C

HH

CH3

H

CH3H

CH3H

H

H

HH3C

CH3H

H

H

CH3H

H

CH3H

H

CH3

I II III

IV V

H

A) I B) II C) III D) IV E) V

Ans: B Topic: Conformational Analysis 41. The preferred conformation of cis-3-tert-butyl-1-methylcyclohexane is the one in which:

A) the tert-butyl group is axial and the methyl group is equatorial. B) the methyl group is axial and the tert-butyl group is equatorial. C) both groups are axial. D) both groups are equatorial. E) the molecule exists in a boat conformation.

Ans: D

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42. What structure represents the most stable conformation of cis-1,3-dimethylcyclohexane?

H

H3C

H

CH3

CH3

H

H

H3C

H

CH3

H

H3C

CH3

HCH3

HI II III

H

CH3

H

H3C

VIV

A) I B) II C) III D) IV E) V

Ans: B Topic: Ring Strain

43. Which cycloalkane has the largest heat of combustion per CH2 group?

I II III

VIVA) I B) II C) III D) IV E) V

Ans: A

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Topic: Ring Strain

44. Which cycloalkane has the lowest heat of combustion per CH2 group?

I II III

VIV

A) I B) II C) III D) IV E) V

Ans: D Topic: Ring Strain 45. Which isomer would have the largest heat of combustion?

A) Propylcyclopropane B) Ethylcyclobutane C) Methylcyclopentane D) Cyclohexane E) Since they are all isomers, all would have the same heat of combustion.

Ans: A Topic: Ring Strain

46. Which is the most stable conformation of cyclohexane? A) Chair B) Twist C) Boat D) One-half chair E) Staggered

Ans: A

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47. Which cycloalkane has the greatest ring strain? A) Cyclopropane B) Cyclobutane C) Cyclopentane D) Cyclohexane E) Cycloheptane

Ans: A Topic: Conformational Analysis

48. The most stable conformation of butane is:

HH3C

H

H

HH3C

HH

CH3

H

CH3H

CH3H

H

H

HH3C

CH3H

H

H

CH3H

H

CH3H

H

CH3

I II III

IV V

H

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Conformational Analysis

49. The most stable conformation of 1,2-dibromoethane is:

H

BrH

H

BrH

HBr

H

H

HBr

HH

Br

H

BrH

BrH

H

H

HBr

BrH

H

H

BrH

I II III

IV VA) I B) II C) III D) IV E) V

Ans: C

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Topic: Conformational Analysis

50. The most stable conformation of 2,3-dibromobutane, viewed through the C-2—C-3 bond :

H

BrH3C

H

BrH3C

HBr

CH3

CH3

HBr

HH3C

Br

CH3

BrH

BrH3C

H

H

CH3Br

HH3C

Br

Br

HH3C

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: C

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51. The most stable conformation of 3-bromo-2-methylpentane, viewed through the C-3—C-4 bond (i.e., C-3 in the front, C-4 in the back):

BrH

CH(CH3)2

H

CH3H

III

H

CH(CH3)2H

Br

CH3H

II

HBr

CH(CH3)2

CH3

HH

I

CH(CH3)2Br

H

H

CH3H

IV

CH3H

CH3

CH2CH3

HBr

VA) I B) II C) III D) IV E) V

Ans: A

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Topic: Conformational Analysis

52. The most stable conformation of 3-bromo-2-methylpentane, viewed through the C-2—C-3 bond (i.e., C-2 in the front, C-3 in the back):

H

CH2CH3H3C

Br

CH3H

II

CH3H

CH3

H

CH3Br

I

CH3H

CH3

CH2CH3

HBr

V

BrH

CH(CH3)2

H

CH3H

III

CH2CH3Br

H

CH3

CH3H

IV

A) I B) II C) III D) IV E) V

Ans: E

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53. The most stable conformation of 2,3-dimethylpentane, viewed through the C-2—C-3 bond (i.e., C-2 in the front, C-3 in the back):

H

HH3C

CH3

CH2CH3H

II

CH3H

CH3

CH3

CH2CH3H

I

CH3H

CH3

CH(CH3)2

HH3C

V

CH3H

CH(CH3)2

CH3

HH

III

CH3H

CH3

CH3

HH3CH2C

IV

A) I B) II C) III D) IV E) V

Ans: D Topic: Ring Strain 54. Which cycloalkane has the least ring strain?

A) Cyclopropane B) Cyclobutane C) Cyclopentane D) Cyclohexane E) Cycloheptane

Ans: D Topic: Conformational Analysis

55. The most stable conformation of cis-1-tert-butyl-2-methylcyclohexane is the one in which:

A) the tert-butyl group is axial and the methyl group is equatorial. B) the methyl group is axial and the tert-butyl group is equatorial. C) both groups are axial. D) both groups are equatorial. E) the twist boat conformation is adopted.

Ans: B

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56. The most stable conformation of trans-1-tert-butyl-2-methylcyclohexane is the one in which:

A) the tert-butyl group is axial and the methyl group is equatorial. B) the methyl group is axial and the tert-butyl group is equatorial. C) both groups are axial. D) both groups are equatorial. E) the molecule is in the half chair conformation.

Ans: D Topic: Conformational Analysis

57. The most stable conformation of trans-1-tert-butyl-3-methylcyclohexane is the one in which:

A) the tert-butyl group is axial and the methyl group is equatorial. B) the methyl group is axial and the tert-butyl group is equatorial. C) both groups are axial. D) both groups are equatorial. E) the twist boat conformation is adopted.

Ans: B Topic: Conformational Analysis

58. In the most stable conformation of cis-1,4-dimethylcyclohexane, the methyl groups are: A) one axial, one equatorial. B) both axial. C) both equatorial. D) alternating between being both axial and both equatorial. E) None of the above

Ans: A

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59. The most stable conformation for 1,2-ethanediol (ethylene glycol) is shown below. It is the most stable conformation because:

OHH

H

H

OHH

A) this corresponds to an anti conformation. B) in general, gauche conformations possess the minimum energy. C) it is stabilized by intramolecular hydrogen bonding. D) it is a staggered conformation. E) it has the highest energy of all the possibilities.

Ans: C Topic: Conformational Analysis

60. The graph below is a plot of the relative energies of the various conformations of:

0o 60o 120o 180o 240o 300o 360o

Rel

ativ

e en

ergy

Angle of rotationA) Ethane B) Propane C) Chloroethane D) 1-Chloropropane (C1-C2 rotation) E) Butane (C1-C2 rotation)

Ans: D

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61. The graph below is a plot of the relative energies of the various conformations of:

0o 60o 120o 180o 240o 300o 360o

Rel

ativ

e en

ergy

Angle of rotationA) 2-chloropropane B) 1,3-dichloropropane C) 2-methylpropane D) Butane (C1-C2 rotation) E) Butane (C2-C3 rotation)

Ans: E Topic: Conformational Analysis

62. Consider the graph below, which is a plot of the relative energies of the various conformations of hexane, viewed through the C2-C3 bond. The conformations corresponding to the 60o and 300o are:

0o 60o 120o 180o 240o 300o 360o

Rel

ativ

e en

ergy

Angle of rotationA) Eclipsed B) Staggered, and gauche C) Staggered and anti D) More stable than the conformation at 180o E) None of the above

Ans: B

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Topic: Conformational Analysis

63. Consider the graph below, which is a plot of the relative energies of the various conformations of 2,3-dimethylbutane, viewed through the C2-C3 bond. The conformations corresponding to the 120o and 240o are:

0o 60o 120o 180o 240o 300o 360o

Rel

ativ

e en

ergy

Angle of rotationA) Eclipsed, more stable than the conformation at 0o B) Eclipsed, more stable than the conformation at 180o C) Staggered, more stable than the conformation at 0o D) Staggered, less stable than the conformation at 180o E) Two of the above are true

Ans: A Topic: Conformational Analysis 64. Which conformation of trans-1-isopropyl-3-methylcyclohexane would be present in

greatest amount at equilibrium? A) The conformation with the methyl group equatorial and the isopropyl group axial B) The conformation with the methyl group axial and the isopropyl group equatorial C) The conformation with both groups axial D) The conformation with both groups equatorial E) The twist boat conformation.

Ans: B

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65. Which conformation represents the most stable conformation of trans-1-bromo-4-methylcyclohexane?

CH3

Br

Br

CH3

CH3Br

BrH3C

BrCH3

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: A Topic: Cis-Trans Isomers

66. Which of the following can be described as cis isomers?

CH3

CH2CH3

Cl

CH3

BrHO

CH3HO

BrF

I II III

IV V

A) I B) II, V C) III, IV D) I, III and IV E) None of the above are cis isomers.

Ans: B

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Topic: Cis-Trans Isomers

67. Which of the following can be described as trans isomers?

CH3

CH2CH3

Cl

CH3

BrHO

CH3HO

BrF

I II III

IV V

A) I B) II, V C) III, IV D) I, III and IV E) None of the above are trans isomers.

Ans: C Topic: Conformational Analysis

68. Which of the following will have the same energy after undergoing ring flip?

CH2CH3

CH2CH3

Cl

CH3

OHHO

CH3HO

BrF

I II III

IV V

A) I B) II C) III D) IV E) V.

Ans: E

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Topic: Conformational Analysis

69. The least stable conformation of cyclohexane is the: A) boat. B) twist boat. C) chair. D) half-chair. E) twist chair.

Ans: D Topic: Conformational Analysis

70. Express, quantitatively, the difference in stability of the two structures shown below.

H3C

CH3CH3H3C

I II

A) I is more stable than II by 7.5 kJ mol-1. B) I is more stable than II by 15 kJ mol-1. C) II is more stable than I by 7.5 kJ mol-1. D) II is more stable than I by 15 kJ mol-1. E) The two are equal in stability.

Ans: A Topic: Conformational Analysis

71. The twist boat conformation is the preferred conformation for this compound. A) cis-1,4-Di-tert-butylcyclohexane B) trans-1,4-Di-tert-butylcyclohexane C) cis-1,3-Di-tert-butylcyclohexane D) trans-1,2-Di-tert-butylcyclohexane E) None of these

Ans: A

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Topic: Ring Strain

72. Which of these C10H18 isomers is predicted to be the most stable?

I II III

IV V

H

H

H

H

A) I B) II C) III D) IV E) V

Ans: E Topic: Alkane Synthesis

73. Select the reagents necessary to convert cyclopentene into cyclopentane. A) H2 and Ni B) H2O C) Heat D) Zn, H3O+ E) Light

Ans: A Topic: Alkane Synthesis

74. Select the reagents necessary to convert 3-bromohexane into hexane. A) Zn, H3O+ B) CuI C) H2O D) H3O+ E) OH-

Ans: A

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Topic: General

75. How many constitutional isomers are possible for the formula C6H14? A) 2 B) 3 C) 4 D) 5 E) 6

Ans: D Topic: General

76. How many compounds with the formula C7H16 (heptanes) contain a single 3° carbon atom?

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: C Topic: Alkane Synthesis, Nomenclature

77. Catalytic hydrogenation of which of the following will yield 2-methylpentane? A) 2-methyl-1-pentene

2 B) 2-methyl-2-pentene

C) 4-methyl-2-pentene

D) 4-methyl-1-pentene

E) All of the above Ans: E

Topic: Alkane Synthesis, Nomenclature

78. The synthesis of an alkyne precursor to 2,2-dimethylheptane is accomplished most effectively by the reaction between these two reagents:

A) CH3CH2CH2C≡CNa and (CH3)3CBr B) CH3CH2C≡CNa and (CH3)3CCH2Br C) (CH3)3CC≡CNa and CH3CH2CH2Br D) (CH3)3CCH2CH2C≡CH and CH3CH2I E) HC≡CNa and (CH3)3CCH2CH2Br

Ans: C

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Topic: Alkane Synthesis, Nomenclature

79. The reaction of the Na salt of 3-methyl-1-pentyne with 1-bromo-3-methylbutane produces which of these?

A) 3,8-dimethyl-4-nonyne B) 2,7-dimethyl-4-nonyne C) 3,8-dimethyl-5-nonyne D) 3,7-dimethyl-4-nonyne E) 3,7-dimethyl-5-nonyne

Ans: A Topic: General

80. What is the simplest alkane, i.e., the one with the smallest molecular weight, which possesses primary, secondary and tertiary carbon atoms?

A) 2-Methylpropane B) 2-Methylbutane C) 2-Methylpentane D) 3-Methylpentane E) 2,2-Dimethylbutane

Ans: B Topic: General

81. How many alkanes of formula C7H16 possess a quaternary carbon atom? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C SHORT ANSWER QUESTIONS Topic: General

82. To determine the parent name for an alkane, we begin by finding the ___________________________. Ans: longest continuous chain of carbons

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Topic: Nomenclature

83. When more than one substituent is present on the parent chain, how do we organize the names of the substituents in the name of the compound? ___________________________. Ans: alphabetical order

Topic: General

84. A compound containing two fused or bridged rings is referred to as a ___________________________. Ans: bicycloalkane

Topic: General

85. A compound containing a triple bond between the first two carbons in the chain is called a ___________________________. Ans: terminal alkyne

Topic: General

86. When non-bonded atoms/groups are closely positioned, the repulsive interactions between their electron clouds are referred to as ___________________________. Ans: steric hindrance

Topic: General

87. _____________________ have the same molecular formula and connectivity but different arrangements of atoms in three-dimensional space. Ans: Stereoisomers

Topic: Nomenclature

88. Alkanes in which some or all of the carbon atoms are arranged in a ring are called ___________________________. Ans: cycloalkanes

Topic: Nomenclature

89. What is the fundamental principle of the IUPAC system of nomenclature for organic compounds? Ans: Each different compound should have an unambiguous name.

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Topic: Nomenclature

90. What are the four possible parts of a IUPAC name? Ans: locant, prefix, parent name, suffix

Topic: General

91. In a bicyclic compound, the carbon atoms common to both rings are called ___________________________. Ans: bridgeheads

Topic: Nomenclature 92. Give the IUPAC name corresponding to the following structure.

Br

OH Ans: 5-bromo-6-cyclopentyl-2-hexanol

Topic: Nomenclature 93. Give the IUPAC name corresponding to the following structure:

BrHO

Ans: 3-(2-bromobutyl)cyclopentanol

Topic: Nomenclature 94. Give the IUPAC name corresponding to the following structure:

Br

F Ans: trans-1-bromo-2-fluorocyclohexane

Topic: Nomenclature 95. Give the IUPAC name corresponding to the following structure:

HO

Ans: 3-ethyl-6,7-dimethyl-2-octanol

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Topic: Nomenclature, Conformations 96. Draw the bond-line structural formula corresponding to the most stable conformation of

the following substance: trans-1-bromo-3-(1-methylpropyl)cyclohexane Ans: Br

Topic: Nomenclature 97. Draw the bond-line structural formula corresponding to the name: 2,5,9-trimethyl-2-

decen-7-yne Ans:

Topic: Alkane Conformations 98. Draw the Newman projection formula for the gauche conformation of the C2-C3 bond

in pentane. Ans:

HH

CH3

H

CH2CH3H

Topic: Alkane Conformations 99. Draw the Newman projection formula for the most stable conformation of the C2-C3

bond in 3-methylpentane. Ans:

HH

CH3

CH2CH3

CH3H

Topic: Alkane Synthesis 100. Complete the following reaction sequence, giving structural details of A, B and C.

NaH

AC2H5Br

BH2,Ni

C

Ans: NaH C2H5Br

ANa+

B

H2,Ni

C

:

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MULTIPLE CHOICE QUESTIONS Topic: Identifications and Comparisons

1. Which of the following is the enantiomer of the following substance? H

CH3BrH

H

CH3HBr

CH3

H HBr

CH3

H BrH

I II III A) I B) II C) III D) It does not have a non-superposable enantiomer. E) Both II and III Ans: D

Topic: Identifications and Comparisons

2. Which of the following molecules is achiral?

CC CH3C

H

H

CH3

Br

FClH

CO2H

OH

OHH

HHO2C

CO2H

CO2H

OHH

HHOBr

CH2CH3

CH3

HO

I II III

IV V A) I B) II C) III D) IV E) V Ans: B

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3. Hexane and 3-methylpentane are examples of: A) enantiomers. B) stereoisomers. C) diastereomers. D) constitutional isomers. E) None of these Ans: D

Topic: Identifications and Comparisons

4. I and II are:

H

H3C Cl

CH2CH3

CH2CH3

H H

CH2Cl

I II A) constitutional isomers. B) enantiomers. C) non-superposable mirror images. D) diastereomers. E) not isomeric. Ans: A

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Topic: Identifications and Comparisons

5. Pairs of enantiomers are:

CH2CH2CH3

H3C Cl

CH3

CH2CH2CH3

Cl CH3

CH3

I II

H

H3C Cl

CH2CH2CH3

CH2CH2CH3

H H

CH2Cl

IV V

CH2CH2CH3

H3C Cl

H

III

A) I, II and III, IV B) I, II C) III, IV D) IV, V E) None of the structures Ans: C

Topic: Identifications and Comparisons

6. Chiral molecules are represented by:

C2H5

ClH3C

CH3

IC2H5

CH3Cl

CH3

IIC2H5

ClH3C

H

III

H

ClH3C

C2H5

IVC2H5

HH

CH2Cl

VA) I, II, III, IV and V B) I, II, III and IV C) I and II D) III and IV E) IV alone Ans: D

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Topic: Identifications and Comparisons

7. The molecules shown are: H

CH3

OHH

BrH

H

CH3

OHH

HBr

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: B

Topic: Identifications and Comparisons

8. The

The molecules shown are: Cl

CH2CH3

HH3CH2C

ClH

H

CH2CH3

CH2CH3Cl

HCland are

A) enantiomers. B) diastereomers. C) constitutional isomers. D) two conformations of the same molecule. E) not isomeric. Ans: B

Topic: Identifications and Comparisons

9. The molecules shown are: CH3

HF

H

H

CH3

H

F A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: B

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Topic: Identifications and Comparisons

10. The molecules below are: H

F

F

H

H

FH

F A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) stereoisomers. Ans: A

Topic: Identifications and Comparisons

11. The molecules shown are: CH3

CH3

HCl

ClH

H

CH3

CH3Cl

HCl

A) enantiomers. B) diastereomers. C) constitutional isomers. D) two different conformations of the same molecule. E) not isomeric. Ans: A

Topic: Identifications and Comparisons

12. The molecules shown are: CH3

OH

H

H

OH

HH

CH3

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: B

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Topic: Identifications and Comparisons

13. The molecules shown are:

F

HH

F

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: E

Topic: Identifications and Comparisons

14. The molecules below are: H

H

CH3

CH3

H

CH3

H

CH3

A) structural isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: C

Topic: Identifications and Comparisons

15. Cis-trans isomers are: A) diastereomers. B) enantiomers. C) stereoisomers. D) constitutional isomers. E) More than one of these Ans: E

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Topic: Identifications and Comparisons

16. The molecules below are:

Br

FCl

CH3

I

CH3

FBr

Cl

II A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: D

Topic: Identifications and Comparisons

17. The molecules below are: CH3

F

FH

CH3H2N

F

FH3C

CH3

NH2

H

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: C

Topic: Identifications and Comparisons

18. The molecules shown are: CH3

F

H

F

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: A

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Topic: Identifications and Comparisons

19. The molecules below are:

H

ClF

CH3

CH3

HF

Cl

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: D

Topic: Identifications and Comparisons

20. The molecules below are: H

ClH

CH3

H

CH3

H

Cl A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: B

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Topic: Identifications and Comparisons

21. Which molecule is achiral? H

Cl

BrCl

HBr

H

ClH

Cl

Br

Br Cl

BrCl

H

Br

Br

I II III A) I B) II C) III D) More than one of these E) None of these Ans: A

Topic: Identifications and Comparisons

22. Which molecule is achiral? H

Cl

BrH

BrH

Cl

BrCl

Br

H

H Cl

ClBr

Br

H

H

I II III A) I B) II C) III D) More than one of the above E) None of the above Ans: C

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Topic: Identifications and Comparisons

23. The molecules below are: H

FH

FHH H

H

I II

HHF

HHH F

H

A) constitutional isomers. B) enantiomers. C) diastereomers. D) identical. E) None of these Ans: A

Topic: Identifications and Comparisons

24. The structures

CH3

H CH3

H

CH3

H CH3

H

represent: A) a single compound. B) enantiomers. C) meso forms. D) diastereomers. E) conformational isomers. Ans: A

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Topic: Identifications and Comparisons

25. Which pair of structures represents the same compound? CH3

OHHOHH

H OHCH3

I II

CH3OHHHHO

H OHCH3

CH3OHHHHO

HO HCH3

III IV

CH3HHOHHO

H OHCH3

V

CH3OHHOHH

HO HCH3

A) I and II B) II and III C) III and IV D) III and V E) IV and V Ans: D

Topic: Identifications and Comparisons

26. Which structure(s) represent(s) diastereomer(s) of I?

CH3OHHHHO

HO HCH3

I II

CH3OHHHHO

H OHCH3

CH3OHHOHH

H OHCH3

III IV

CH3HHOHHO

H OHCH3

V

CH3OHHOHH

HO HCH3

A) II B) II and III C) II and IV D) III and V E) IV and V Ans: B

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Topic: Identifications and Comparisons

27. The two compounds shown below are: Br

FHCl

F

ClBrH

A) enantiomers. B) diastereomers. C) constitutional isomers. D) identical. E) different but not isomeric. Ans: A

Topic: Identifications and Comparisons

28. The two compounds shown below are:

Br

HBr

H Br

HBr

Hand

are: A) identical. B) enantiomers. C) diastereomers. D) conformational isomers. E) meso forms. Ans: B

Topic: Identifications and Comparisons

29. (2R,4S) –2,4–Dichloropentane and (2S,4R)-2,4-dichloropentane are: A) enantiomers B) diastereomers C) identical D) conformational isomers E) constitutional isomers Ans: C

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Topic: Meso compounds

30. Which of the following is a meso compound? H

HOH3C

CH3

H

OH

CH3

CH2OH

OHH

CH2OH

CH2OH

HH

CH2OH

CH3

OHH

H H2C

H3CHO

CH3

H

OH

I II

III IV V A) I B) II C) III D) IV E) V Ans: A

Topic: Meso compounds

31. Which of the following is(are) meso compound(s)? H

CH3

CH3Cl

ClH

Cl

ClH

CH3

CH3

H H

ClH

CH3

CH3

Cl

I II III A) I B) II C) III D) Both II and III E) Both I and III Ans: E

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Topic: Meso compounds

32. Which of the following molecules is achiral? A) (2R,3R)-2,3-Dichloropentane B) (2R,3S)-2,3-Dichloropentane C) (2S,4S)-2,4-Dichloropentane D) (2S,4R)-2,4-Dichloropentane E) Two of these Ans: D

Topic: Meso compounds

33. Which of the following is(are) meso? Br

Br

Br

H

H

Br

Br

H

H

Br

Br

H

Br

H

I II III IVA) I B) II C) III D) IV E) Two of the above Ans: E

Topic: Meso compounds

34. Which molecule has a plane of symmetry? F

Cl

HClHH

H

CH3

Cl

H

H

CH3

CH3

H

I II IIIA) I B) II C) III D) More than one of these E) None of these Ans: D

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Topic: Meso compounds

35. Which molecule has a plane of symmetry?

CH3HO

H CH3 CH2CH3

CH3HOH

H

F

H

F

I II III A) I B) II C) III D) More than one of these E) None of these Ans: D

Topic: Meso compounds

36. Which compound does NOT possess a plane of symmetry?

H

F

H

F

I

H

CH3

Cl

H

II

Br

H

H

Br

III

Br

Br

CH3

H3CIV V

A) I, II and V B) I, III and IV C) II, III and IV D) III and IV E) V Ans: D

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Topic: Meso compounds

37. Which molecule is a meso compound? CH3

CH3

BrH

BrH

H3C

CH3H

H

OH

OH H3C

FH

H

CH3

F

I II III A) I B) II C) III D) More than one of the above E) None of the above Ans: D

Topic: Meso compounds

38. Which molecule is a meso compound? H

OH

H

F

I

H

F

F

H

II

H

H

H

F

III

H

H

CH3

CH3

IV

F

F

CH3

CH3

V A) I and II B) IV and V C) II and III D) I, II and III E) None of the above Ans: E

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Topic: Meso compounds

39. Which of the following substances is achiral ? H

CH3

Cl

H

I II III

CH3

HO

IV

H

F

F

H

Br

H

H

Br

A) I B) II C) III D) IV E) More than one of these Ans: E

Topic: Meso compounds

40. Which statement is not true for a meso compound? A) The specific rotation is 0º. B) There are one or more planes of symmetry. C) A single molecule is identical to its mirror image. D) More than one stereogenic center must be present. E) The stereochemical labels, (R) and (S), must be identical for each stereogenic

center. Ans: E

Topic: Meso compounds

41. Which is a meso compound? A) (2R,3R)-2,3-Dibromobutane B) (2R,3S)-2,3-Dibromopentane C) (2R,4R)-2,4-Dibromopentane D) (2R,4S)-2,4-Dibromopentane E) (2R,4S)-2,4-Dibromohexane Ans: D

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Topic: Specific names

42. (R)-2-Chlorobutane is represented by: CH3

CH2CH3

ClH3C

I

CH3

CH2CH3

CH3Cl

II

H

CH2CH3

ClH3C

III

CH2CH3

HClH3C

IV

CH2Cl

CH2CH3

HH

V A) I B) II C) III D) IV E) V Ans: C

Topic: Specific names

43. Which of the following represent (R)-2-butanol? H

CH2CH3

OHH3C

I

CH3

CH2CH3

OHH

II

H

CH2CH3

CH3HO

III

CH3

CH2CH3

HHO

IV

CH2CH3

CH3

OHH

V A) III and V B) I, III, IV and V C) I, IV and V D) I and III E) I, II, IV and V Ans: C

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Topic: Specific names

44. Which structure represents (S)-1-chloro-1-fluoroethane? F

CH3

HCl

I

F

CH3

ClH

II

CH3

FClH

III A) I B) II C) III D) More than one of the above E) None of the above Ans: D

Topic: Specific names

45. Which structure represents (R)-1-chloro-1-fluoroethane? F

CH3

HCl

I

F

CH3

ClH

II

CH3

FClH

III A) I B) II C) III D) More than one of the above E) None of the above Ans: B

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Topic: Specific names

46. Which structure represents (S)-2-bromobutane? CH3

CH2CH3

BrH

I

CH3

CH2CH3

HBr

II

H

CH2CH3

BrH3C

III A) I B) II C) III D) More than one of the above E) None of the above Ans: A

Topic: Specific names

47.

CH2CH3

ClH

CH3HCl H

CH3 is properly named: A) (3R,4S,5R)- 3,5-Dichloro-4-methylhexane B) (2S,3S,4S)- 2,4-Dichloro-3-methylhexane C) (2S,3R,4R)- 2,4-Dichloro-3-methylhexane D) (2S,3R,4S)-2,4-Dichloro-3-methylhexane E) (2S,3S,4R)- 2,4-Dichloro-3-methylhexane Ans: D

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Topic: Specific names

48. The Cahn-Ingold-Prelog stereochemical designations used for the following substance are:

H

ClH

Cl

Cl

Cl A) 2R,4S B) 2S,4R C) 2R,4R D) 2S,4S E) The “R,S” terminology doesn't apply in this case. Ans: C

Topic: Specific names

49. Which of these is not a correct Fischer projection formula of the (S) form of 3-bromo-1,1-dichloro-2-propanol ?

CHCl2

CH2BrOHH

I

CH2Br

CHCl2

HHO

II

H

OHCH2BrCl2HC

III

OH

CH2BrCHCl2H

IV

OH

HCHCl2BrH2C

V A) I B) II C) III D) IV E) V Ans: D

Topic: Optical activity

50. What is the percent composition of a mixture of (S)-(+)-2-butanol,[α]D25 = +13.52º,

and (R)-(-)-2-butanol,[α]D25 = -13.52º, with a specific rotation [α]

D25 = +6.76º?

A) 75%(R) 25%(S) B) 25%(R) 75%(S) C) 50%(R) 50%(S) D) 67%(R) 33%(S) E) 33%(R) 67%(S) Ans: B

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Topic: Optical activity

51. Which one of the following can exist in optically active forms? A) cis-1,3-Dichlorocyclohexane B) trans-1,3-Dichlorocyclohexane C) cis-1,4-Dichlorocyclohexane D) trans-1,4-Dichlorocyclohexane E) cis-1,2-Dichlorocyclohexane Ans: B

Topic: Optical activity

52. The compounds whose molecules are shown below would have: CH3

CH2CH3

FH

I

CH2CH3

CH3

FH

II A) the same melting point. B) different melting points. C) equal but opposite optical rotations. D) More than one of the above E) None of the above Ans: D

Topic: Optical activity

53. The compounds whose molecules are shown below would have: CH3

F

FH

CH3H

F

FH3C

CH3

H

H

A) the same melting point. B) different melting points. C) equal but opposite optical rotations. D) More than one of the above E) None of the above Ans: B

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Topic: Optical activity

54. The compounds whose molecules are shown below would have:

H

OH

H

OH

H

OHOH

H

A) the same melting point. B) different melting points. C) equal but opposite optical rotations. D) More than one of these E) None of these Ans: B

Topic: Optical activity

55. The compounds whose structures are shown below would have:

Br

CH3

CH3

Br

Br

CH3

CH3

Br

A) the same melting point. B) different melting points. C) equal but opposite optical rotations. D) More than one of these E) None of these Ans: D

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Topic: Optical activity

56. A solution of which of these allenes will rotate plane-polarized light?

C C C

H

H H

H

C C C

H

Cl H

H

C C C

H

Cl Cl

H

C C C

Cl

Cl Cl

H

C C C

Cl

Cl Cl

Cl

I II III

IV V A) I B) II C) III D) IV E) V Ans: C

Topic: Optical activity

57. How many optically active compounds are represented by the following generalized formula?

BrHC CHBr

A) 0 B) 1 C) 2 D) 3 E) 4 Ans: C

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Topic: Optical activity

58. Which of these is a comparatively insignificant factor affecting the magnitude of specific optical rotation? A) Concentration of the substance of interest B) Purity of the sample C) Temperature of the measurement D) Length of the sample tube E) All of the above are equally significant. Ans: C

Topic: Optical activity

59. What can be said with certainty if a compound has [α]D25 = -9.25º ?

A) The compound has the (S) configuration. B) The compound has the (R) configuration. C) The compound is not a meso form. D) The compound possesses only one stereogenic center. E) The compound has an optical purity of less than 100%. Ans: C

Topic: Optical activity

60. An alkane which can exhibit optical activity is: A) Neopentane B) Isopentane C) 3–Methylpentane D) 3–Methylhexane E) 2,3–Dimethylbutane Ans: D

Topic: Optical activity

61. In the absence of specific data, it can only be said that (R)–2–bromopentane is: A) dextrorotatory (+). B) levorotatory (–). C) optically inactive. D) achiral. E) analogous in absolute configuration to (R)–2–chloropentane. Ans: E

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Topic: Optical activity

62. If a solution of a compound (30.0 g/100 mL of solution) has a measured rotation of +15º in a 2 dm tube, the specific rotation is: A) +50º B) +25º C) +15º D) +7.5º E) +4.0º Ans: B

Topic: Optical activity

63. Which compound would show optical activity? A) cis 1,4- Dimethylcyclohexane B) trans 1,4- Dimethylcyclohexane C) cis 1,4- Dimethylcycloheptane D) trans 1,4- Dimethylcycloheptane E) More than one of these Ans: D

Topic: Optical activity

64. Of the compounds which correspond to the general name "dichlorocyclobutane", how many are optically active? A) 0 B) 1 C) 2 D) 3 E) 4 Ans: C

Topic: General definitions

65. Which of the following is true about any (R)-enantiomer? A) It is dextrorotatory. B) It is levorotatory. C) It is an equal mixture of + and -. D) It is the mirror image of the (S)-enantiomer. E) (R) indicates a racemic mixture. Ans: D

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Topic: General definitions

66. Which of the following is true of any (S)-enantiomer? A) It rotates plane-polarized light to the right. B) It rotates plane-polarized light to the left. C) It is a racemic form. D) It is the mirror image of the corresponding (R)-enantiomer. E) It has the highest priority group on the left. Ans: D

Topic: General definitions

67. Enantiomers are: A) molecules that have a mirror image. B) molecules that have at least one stereogenic center. C) non-superposable molecules. D) non-superposable constitutional isomers. E) non-superposable molecules that are mirror images of each other. Ans: E

Topic: General definitions

68. Which of the following is NOT true of enantiomers? They have the same: A) boiling point. B) melting point. C) specific rotation. D) density. E) chemical reactivity toward achiral reagents. Ans: C

Topic: General definitions

69. Which statement is true of 1,3-dimethylcyclobutane? A) Only one form of the compound is possible. B) Two diastereomeric forms are possible. C) Two sets of enantiomers are possible. D) Two enantiomeric forms and one meso compound are possible. E) None of the previous statements is true. Ans: B

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Topic: Reaction stereochemistry

70. In which of the following reactions is the absolute configuration of the product likely to be the same as that of the reactant? A)

OHBr PBr3

BrBr

(R)B)

OHBr

OH

O

OBr

O

(R)HA

C) OH

Br H2OOH

OH(R)

D) All of the above E) Answers A) and B) only Ans: E

Topic: Reaction Stereochemistry

71. Which of the following reactions must occur with retention of configuration? A)

OH

KMnO4

O

(R)

B)

OH Cl

(R)POCl3

C) OH

Cl

O

NH3OH

NH2

O

(S)

D) OH

O

OCH3 PCl5Cl

O

OCH3(R)

E) (S) OH

O

Cl P, Cl2OH

O

Cl Cl

Ans: D

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72. Which reaction must take place with retention of configuration at the stereogenic center? A)

BrHCl

BrOH Cl

F F

B) OHF

PCl3ClF

C)

OHF

OFO

O O

OD) More than one of the above E) None of the above Ans: D

Topic: Reaction stereochemistry

73.

The reaction of O with H2/Ni forms: A) 2-methylheptane. B) (R)-2-methyl-5-heptanol C) (S)-6-methyl-3-heptanol D) (R,S)-6-methyl-3-heptanol E) Achiral 6,6-dimethyl-3-hexanol Ans: D

Topic: General stereochemistry

74. CH3CHBrCH2CHClCH3 is the generalized representation of what number of stereoisomers? A) 3 B) 4 C) 5 D) 6 E) 7 Ans: Bs

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Topic: General stereochemistry

75. For the generalized structure BrCH2CHClCH2CHClCH2Br there exists what number of stereoisomers? A) 2 B) 3 C) 4 D) 6 E) 8 Ans: B

Topic: General stereochemistry

76. How many discrete dimethylcyclopropanes are there? A) 2 B) 3 C) 4 D) 5 E) 6 Ans: C

Topic: General stereochemistry

77. What is the molecular formula for the alkane of smallest molecular weight which possesses a stereogenic center? A) C4H10 B) C5H12 C) C6H14 D) C7H16 E) C8H18 Ans: D

Topic: General stereochemistry

78. How many chiral stereoisomers can be drawn for CH3CHFCHFCH(CH3)2? A) 1 B) 2 C) 3 D) 4 E) 8 Ans: D

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Topic: General stereochemistry

79. How many different compounds are there which correspond to the general name "3-(1-methylbutyl)cyclobutanol”? A) 2 B) 4 C) 6 D) 8 E) None of the above Ans: B

Topic: General stereochemistry

80. How many stereogenic centers are there in Lovastatin ( Mevacor® : a cholesterol-lowering drug) ?

O

HO

O

O

(Lovastatin) A) 4 B) 5 C) 6 D) 7 E) 8 Ans: E

Topic: General stereochemistry

81. What is the total number of compounds, stereoisomers included, designated by the general name "dichlorocyclopentane"? A) 4 B) 5 C) 7 D) 8 E) 9 Ans: C

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Use the following to answer questions 82-85: Consider the following compounds:

CH2OH

CH3

OHH

HH

HO

CH3H

H

OH

CH3 HO

CH3HO

CH3

H

H

I II III

H

HH3C

CH3

OH

OH

IV Topic: General stereochemistry

82. Which of the compounds above (I-IV) represent enantiomers? A) I and II B) II and III C) III and IV D) II and IV E) III and IV Ans: B

Topic: General stereochemistry

83. Which compound above (I-IV) is a meso compound? A) I B) II C) III D) IV E) None of these Ans: D

Topic: General stereochemistry

84. Which compound above (I-IV) is (2R,3R)-2,3-butanediol? A) I B) II C) III D) IV E) None of these Ans: C

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Topic: General stereochemistry

85. Which compounds above (I-IV) form a set of stereoisomers? A) I, II and III B) II, III and IV C) II and III D) I, III and IV E) I, II, III and IV Ans: B

SHORT ANSWER QUESTIONS Topic: General stereochemistry

86. To be superposable, when one object is placed on top of another, _________________. Ans: all parts of each object must coincide

Topic: General stereochemistry

87. An achiral molecule is one that is __________________ upon its mirror image. Ans: superposable

Topic: General stereochemistry

88. Enantiomers are stereoisomers whose molecules are ____________________. Ans: nonsuperposable mirror images

Topic: General stereochemistry

89. A chiral molecule is defined as one that is _____________________ on its mirror image. Ans: nonsuperposable

Topic: General stereochemistry

90. A meso compound has __________ chiral center(s), and is __________ upon its mirror image. Ans: two or more, superposable

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Topic: General stereochemistry

91. The molecule of aspartame ( Nutrasweet® ), depicted below, has ___________ ( how many? ) stereogenic centers.

H2N

HNOHO

OO

O

Aspartame Ans: two

Topic: General stereochemistry

92. All molecules with a plane of symmetry are _________. Ans: achiral

Topic: General stereochemistry

93. When using the Cahn-Ingold-Prelog rules for prioritizing groups on a stereogenic carbon, priority is first assigned on the basis of ____________________. Ans: atomic number

Topic: General stereochemistry

94. Enantiomers have ______________ physical properties. Ans: identical

Topic: General stereochemistry

95. The device that is used for measuring the effect of optically active compounds on plane-polarized light is called a ________________. Ans: polarimeter

Topic: General stereochemistry

96. True or false: A sample consisting of the pure R enantiomer of a compound will always rotate plane-polarized light in a clockwise direction. A) True B) False Ans: B

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Topic: General stereochemistry

97. An equimolar mixture of two enantiomers is called a ________________. Ans: racemic mixture

Topic: General stereochemistry

98. A molecule that contains stereogenic carbons but is nonetheless achiral is referred to as a ______________. Ans: meso compound

Topic: General stereochemistry

99. When discussing the stereochemical relationship of cis/trans isomers of cyclic compounds, we refer to them as __________________. Ans: diastereomers

Topic: Nomenclature

100. Draw a dash-wedge structure for (3R)-3-methyl-5-hexen-3-ol Ans: OH

Topic: Nomenclature

101. Draw a dash-wedge structure for (1R)-1-bromo-1,3,3-trimethylcyclohexane Ans:

Br

Topic: Nomenclature

102. Draw a dash-wedge structure for (1R,3R)-1,3-dibromo-1,3-dimethylcyclohexane Ans:

Br

Br

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Topic: Nomenclature

103. Draw a dash-wedge structure for (1S,3R)-1-ethyl-1,3-dimethylcyclopentane Ans: CH3

H CH3

C2H5

Topic: Nomenclature

104. What is the complete IUPAC name of the following substance? (Remember to give stereochemical details, as relevant.)

H

H3C CH3

C2H5

Ans: (1S)-1-ethyl-1,3,3-trimethylcyclopentane

Topic: Nomenclature

105. What is the complete IUPAC name of the following substance? (Remember to give stereochemical details, as relevant.)

H

H3C OH

OH

Ans: (1R,3S)-1-methylcyclopentane-1,3-diol

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Topic: Fischer projections

106. Draw Fischer projection formulas for all stereoisomers of 2,4-dibromohexane, giving stereochemical details for each structure. Ans:

2,4-dibromohexane

CH3

HBr

HH

HBr

HH

CH3

CH3

BrH

HH

HBr

HH

CH3

CH3

HBr

HH

BrH

HH

CH3

2R,4S

CH3

BrH

HH

BrH

HH

CH3

2S,4R 2S,4S 2R,4R

Topic: Stereoisomers

107. Draw dash-wedge structures for all stereoisomers of 1-bromo-3-isopropylcyclohexane, giving stereochemical details for each structure. Ans:

H

H Br

H

Br H

H

H Br

H

Br H

1-bromo-3-isopropylcyclohexane

1S, 3R 1R, 3S 1S, 3S 1R, 3R

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Topic: Fischer projections

108. Draw Fischer projection formulas for all stereoisomers of 2,4-dimethyl-3-hexanol, giving stereochemical details for each structure. Ans:

CH3

HH3C

OHH

HH3C

HH

CH3

CH3

HH3C

OHH

CH3H

HH

CH3

CH3

HH3C

HHO

HH3C

HH

CH3

CH3

HH3C

HHO

CH3H

HH

CH3

3S,4S 3R,4R 3S,4R 3R,4S

2,4-dimethyl-3-hexanol Topic: Fischer projections

109. Draw a Fischer projection formula of (3R)-6-Bromo-1-hexen-3-ol. Ans:

OH

Br

H2C

OHH

HH

HH

CH2Br

H

(3R)-6-Bromo-1-hexen-3-ol.

*

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MULTIPLE CHOICE QUESTIONS Topic: Reaction kinetics

1. Consider the SN2 reaction of butyl bromide with OH- ion. CH3CH2CH2CH2Br + OH- ⎯⎯⎯⎯→ CH3CH2CH2CH2OH + Br-

Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both butyl bromide and OH- ion?

A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times.

Ans: D Topic: Reaction kinetics

2. Consider the SN2 reaction of 2-iodopentane with CH3CO2− ion.

I

ONa

O OONaI

Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH3CO2− ion?

A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times.

Ans: D

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Topic: Reaction kinetics

3. Consider the SN2 reaction of 1-chloro-5-methylhexane with CN− ion.

Cl NaCN CN NaCl

Assuming no other changes, what effect on the rate would result from simultaneously doubling the concentrations of both 1-chloro-5-methylhexane and CN− ion?

A) No effect. B) It would double the rate. C) It would triple the rate. D) It would increase the rate four times. E) It would increase the rate six times.

Ans: D Topic: Reaction kinetics

4. Select the rate law for the following reaction, e.g., CH3CH2CH2CHBrCH3 + OH− ⎯⎯⎯→ CH3CH2CH2CHOHCH3 + X− ( RBr )

A) Rate = k [RBr] B) Rate = k [RBr] [OH−] C) Rate = k [RBr]2 [OH−] D) Rate = k [RBr] [OH−]2 E) Rate = k [RBr]2 [OH−]2

Ans: B Topic: Activation Energy

5. Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction. The most important reason for this is that increasing the temperature:

A) Increases the collision frequency. B) Decreases the probability factor. C) Increases the fraction of collisions with energy greater than Eact. D) Decreases the energy of activation. E) Makes the reaction more exothermic

Ans: C

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Topic: Activation Energy

6. Increasing the temperature of a chemical reaction usually increases greatly the rate of the reaction. The primary reason for this is that increasing the temperature:

A) Decreases the energy of activation. B) Increases the total number of collisions between reactants C) Decreases the rate of the reverse reaction. D) Favors endothermic processes. E) None of the above properly explains the observed increase in reaction rates with

increase in temperature. Ans: E

Topic: Reaction Kinetics

7. The rate equation for a nucleophilic substitution reaction of a tertiary alkyl bromide (R-Br) with I− ion would be:

A) Rate = k [RBr] B) Rate = k [I−] C) Rate = k [RBr][I−] D) Rate = k [RBr]2[I−] E) Rate = k [RBr][I−]2

Ans: A Topic: Reaction Kinetics

8. The rate equation for a nucleophilic substitution reaction of a secondary alkyl chloride (R-Cl) with I− ion would be:

A) Rate = k [RCl] B) Rate = k [I−] C) Rate = k [RCl][I−] D) Rate = k [RCl]2[I−] E) Rate = k [RCl][I−]2

Ans: C

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Topic: Reaction Kinetics

9. Consider the reaction of 2-chloro-2-methylpentane with sodium iodide.

Cl

NaII

NaCl

Assuming no other changes, how would it affect the rate if one simultaneously doubled the concentration of 2-chloro-2-methylpentane and sodium iodide?

A) No effect B) It would double the rate. C) It would triple the rate. D) It would quadruple the rate. E) It would increase the rate five times.

Ans: B Topic: Predicting mechanisms, products

10. What would you expect to be the chief organic product(s) when tert-butyl bromide reacts with sodium acetylide, i.e.,

BrHC C: Na

I

HC CH

IV

II III

?

A) I B) II C) III D) IV E) None of these

Ans: D

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Topic: Predicting mechanisms, products

11. What would you expect to be the chief organic product(s) when 2-bromo-2-methylpentane reacts with sodium propynide, i.e.,

BrC: Na

I

HC CH

IV

II

V

HC CH

III

?

A) I B) II C) III D) IV E) V

Ans: D Topic: Predicting products

12. What product(s) would you expect to obtain from the following SN2 reaction?

Br

HH

CH3

CH3ONa

CH3OH

OCH3

HH

CH3 H

OCH3H

CH3

I II

CH3O

III

Br

H

H

?

A) I B) II C) An equimolar mixture of I and II. D) III E) None of these

Ans: B

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Topic: Predicting mechanisms, products

13. What major product(s) are likely to be obtained from the following reaction?

Cl

H

H

CH3CH2ONa

CH3CH2OH, 65oC

O

H

H H

O

H

I II

Cl

HO

H

III

?

A) I, by predominantly SN2 B) II, by predominantly SN2 C) An equimolar mixture of I and II, by predominantly SN1. D) III, by substitution of the alkyl group, rather than substitution of the chloro group E) Actually, none of these products are likely to be obtained as major products, because

elimination will probably predominate, leading to the formation of an alkene. Ans: E

Topic: Predicting mechanisms, products

14. Treating (CH3)3C-Cl with a mixture of H2O and CH3OH at room temperature would yield:

A) CH2=C(CH3)2 B) (CH3)3COH C) (CH3)3COCH3 D) All of these E) None of these

Ans: D

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Topic: Predicting mechanisms, products

15. Treating 1-bromo-1-methylcyclohexane with CH3OH at room temperature would yield: A)

OCH3

B)

C)

D) All of these E) None of these

Ans: D Topic: Predicting products

16. The major product of the following reaction would be: C H 2 C l

H O C H 3

C H 3

O H −

C H 2 O H

H 3 C O H

C H 3

C H 2 C l

H O H

C H 3

I

I I I IV

C H 2 C l

H O H

C H 3

I I

C H 2 O H

H O C H 3

C H 3

S N 2?

A) I B) II C) III D) IV E) An equimolar mixture of I and II.

Ans: B

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Topic: Predicting mechanisms, products

17. Which would be formed in the following reaction? CH3

BrH3C

H

CH3OH

OCH3

CH3H3C

H

CH3

CH3

CH3

CH2

I

IVIII

II

CH3

OCH3H3C

H

55oC?

A) I B) II C) III D) IV E) All of the above

Ans: E

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Topic: Predicting mechanisms, products

18. Which would be formed in the following reaction? CH3

Br

H

H3COH

O

CH3

O

H

H3C

O

I

III

O

CH3

H

H3C

O

II

IV

50oC?

A) I B) II C) III D) IV E) All of the above

Ans: E

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Topic: Predicting mechanisms, products

19. Which would be the major product of the following reaction?

H

ClH

CH3

OC(CH3)3

I

CH3

H

H

OC(CH3)3

CH3

H

I II

H3C

III

H3C

IV

(CH3)3COH 55oC

?(CH3)3CO−

A) I B) II C) III D) IV E) None of the above

Ans: C

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Topic: Predicting mechanisms, products

20. When 1,4-diiodo-2,2-dimethylbutane (0.10 mol) is treated with 0.10 mol of NaCN in dimethyl sulfoxide at 30°C, the product formed is:

A) NCI

B) ICN

C) both A) and B).

D) NCCN

E) I

Ans: B

Topic: Predicting mechanisms, products

21. The major product(s) of the following reaction is(are):

H

CH3

H

Cl

H

CH3

H

IH

CH3

I

H

I II

CH3

III IV

H

CH3

H

OCH2CH3

NaI, CH3CH2OH

25oC

A) I B) II C) III D) IV E) Equal amounts of I and II

Ans: A

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Topic: Predicting products

22. What would be the major product of the following reaction?

CH2Cl

H CH3

OH−

CH2OH

H3C H

CH2Cl

HO CH3

I

III

II

IV

CH2Cl

H OH

CH2OH

H CH3

SN2

A) I B) II C) III D) IV E) An equimolar mixture of I and II

Ans: B

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Topic: Predicting mechanisms, products

23. What would be the major product(s) of the following reaction?

CH3H3C

H Br

CH3H3C

H OCH3

OCH3H3C

H CH3

I II

H3C CH3 H3C

III IV

CH3O− / CH3OH

55oC

A) I B) II C) III and IV D) I and II E) All of the above

Ans: C

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Topic: Predicting mechanisms, products

24. What would be the major product of the following reaction?

HH3C

H Br

HH3C

H CN

CNH3C

H Br

I II

III IV

CNH3C

H H

HH3C

NC Br

CΝ −

25oC

A) I B) II C) III D) IV E) Equal amounts of I and III

Ans: C Topic: Predicting mechanisms, products

25. What would be the major product obtained when trans-1-bromo-3-methylcyclopentane is allowed to react with NaSH at 25oC?

HH3C

H SH

SHH3C

H H

SHH3C

H Br

HH3C

HS Br

I II III IV

A) I B) II C) III D) IV E) Equal amounts of I and II

Ans: B

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Topic: Synthesis, reagent selection

26. You want to synthesize 3-methyl-2-pentene from 2-chloro-3-methylpentane. Which reagent would you use?

A) HCl, heat B) NH3(aq), 25oC C) CH3CO2Na, CH3CO2H, heat D) CH3CH2ONa, CH3CH2OH, heat E) CH3CH2OH, heat

Ans: D Topic: Predicting mechanisms, products

27. When tert-pentyl chloride undergoes solvolysis in aqueous ethanol at room temperature, there is/are formed:

A)

OH B)

OC2H5 C)

D)

E) All of these

Ans: E Topic: Predicting mechanisms, products

28. Reaction of sodium ethoxide with 1-bromopentane at 30°C yields primarily: A) CH3CH2CH2CH=CH2 B) CH3CH2CH=CHCH3 C) CH3CH2CH2CH2CH3 D) CH3CH2CH2CH2CH2OH E) CH3CH2CH2CH2CH2OCH2CH3

Ans: E

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Topic: Predicting mechanisms, products

29. Heating an alcoholic solution of sodium hydroxide and 1-bromopentane at 60°C yields primarily:

A) B) C) D) OH E) O

Ans: D Topic: Predicting mechanisms, products

30. If 0.10 mol of HSCH2CH2OH reacts at 25°C, sequentially, with 0.20 mol of NaH, 0.10 mol of CH3CH2Br and H2O, which is the major product?

A) HSCH2CH2OCH2CH3 B) CH3CH2SCH2CH2OH C) CH3CH2SCH2CH2OCH2CH3 D) CH2=CH2 E) CH3CH3

Ans: B Topic: Predicting mechanisms, products

31. When 0.10 mol of ICH2CH2CH2CH2Cl reacts with 0.10 mol of NaOCH3 in CH3OH at 40°C, the major product is:

A) CH3OCH2CH2CH2CH2Cl B) CH3OCH2CH2CH2CH2I C) CH3OCH2CH2CH2CH2OCH3 D) CH2=CHCH2CH2Cl E) CH2=CHCH2CH2I

Ans: A Topic: Generalities

32. SN2 reactions of the type, Nu- + RL ⎯⎯⎯⎯→ Nu-R + L-, are favored: A) when tertiary substrates are used. B) by using a high concentration of the nucleophile. C) by using a solvent of high polarity. D) by the use of weak nucleophiles. E) by none of the above.

Ans: B

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Topic: Generalities

33. Which of the following statements is (are) true of SN1 reactions of alkyl halides in general?

A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. B) The rate of an SN1 reaction depends on the concentration of the nucleophile. C) SN1 reactions of alkyl halides are favored by polar solvents. D) Answers A) and C) only are true. E) Answers A), B) and C) are true.

Ans: D Topic: Generalities

34. Which of the following statements is (are) true of SN1 reactions of alkyl halides in general?

A) The rate of an SN1 reaction depends on the concentration of the alkyl halide. B) The rate of an SN1 reaction depends on the concentration of the nucleophile. C) SN1 reactions of alkyl halides occur faster in polar aprotic solvents (compared to protic

solvents) D) Answers A) and C) only are true. E) Answers A), B) and C) are true.

Ans: A Topic: Generalities

35. SN1 reactions of the type, Nu- + RL ⎯⎯⎯⎯→ Nu–R + L-, are favored: A) when tertiary substrates are used. B) by using a high concentration of the nucleophile. C) when L- is a strong base. D) by use of a non-polar solvent. E) by none of the above.

Ans: A Topic: Generalities

36. Which of the following statements is (are) true of an SN2 reaction of (R)-2-bromobutane with hydroxide ion?

A) Doubling the hydroxide ion concentration would double the rate of the reaction. (Assume that all other experimental conditions are unchanged.)

B) The major product would be (S)-2-butanol. C) Doubling the concentration of (R)-2-bromobutane would double the rate of the reaction.

(Assume that all other experimental conditions are unchanged.) D) All of the above E) Two of the above

Ans: D

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Topic: Generalities

37. SN1 reactions of the following type, Nu:- + R-X ⎯⎯⎯⎯→ R-Nu + :X-

are favored: A) by the use of tertiary substrates (as opposed to primary or secondary substrates). B) by increasing the concentration of the nucleophile. C) by increasing the polarity of the solvent. D) by use of a weak nucleophile. E) by more than one of the above.

Ans: E Topic: Generalities

38. SN1 reactions of the following type, Nu:- + R-X ⎯⎯⎯⎯→ R-Nu + :X-

are favored: A) by the use of tertiary substrates (as opposed to primary or secondary substrates). B) by increasing the concentration of the nucleophile. C) by increasing the polarity of the solvent. D) by use of a strong base. E) by more than one of the above.

Ans: A Topic: Generalities

39. A true statement about the transition state(s) of an SN2 reaction is: A) the two transition states are of unequal energy. B) the transition states precede and follow an unstable reaction intermediate. C) the single transition state represents the point of maximum free energy of the reaction. D) existence of this transition state implies an exothermic reaction. E) the transition state will always have a net charge of -1.

Ans: C

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Topic: Generalities

40. Elimination reactions are favored over nucleophilic substitution reactions: A) at high temperatures. B) when tert-butoxide ion is used. C) when 3° alkyl halides are used as substrates. D) when nucleophiles are used which are strong bases and the substrate is a 2° alkyl halide.E) in all of these cases.

Ans: E Topic: Carbocations

41. The hybridization state of the charged carbon in a carbocation is A) sp4 B) sp3 C) sp2 D) sp E) s

Ans: C Topic: Carbocations

42. The p orbital of a methyl cation, CH3+, contains how many electrons?

A) 1 B) 2 C) 3 D) 4 E) 0

Ans: E Topic: Carbocations

43. The p orbital of the charged carbon in the isopropyl cation, (CH3)2CH+, contains how many electrons?

A) 1 B) 2 C) 3 D) 4 E) 0

Ans: E

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Topic: Generalities, solvent effects

44. Considering the relative solvation of reactants and the transition states of SN reactions of these reactants, predict which general type of reaction would be most favored by the use of a polar solvent.

A) Y: + RX ⎯⎯⎯⎯→ RY+ + X:- B) Y:- + RX ⎯⎯⎯⎯→ RY + X:- C) Y: + RX+ ⎯⎯⎯⎯→ RY+ + X: D) Y:- + RX+ ⎯⎯⎯⎯→ RY + X: E) RX+ ⎯⎯⎯⎯→ R+ + X:

Ans: A Topic: Generalities, solvent effects

45. Which is not a polar aprotic solvent? A)

H3CC

CH3

O

B) H3C C N C)

H3CS

CH3

O

D)

HC

N

O

CH3

CH3 E)

H3CCH

OH

CH3

Ans: E

Topic: Generalities, solvent effects

46. Which is a polar aprotic solvent? A) 2-methylhexane B) CH3CN C) NH3(l) D) CH3CH2CH2OCH2CH2CH3 E) 2-methyl-2-propanol

Ans: E

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Topic: Generalities, nucleophiles 47. Identify the nucleophile in the following reaction.

2 H2O + RX ROH + H3O+ + X−

A) X- B) H3O+ C) ROH D) H2O E) RX

Ans: D Topic: Generalities, nucleophiles 48. Identify the nucleophile in the following reaction.

2 R’OH + RX ROR’ + [ROH2]+ + X−

A) X− B) [ROH2]+ C) ROR’ D) R’OH E) RX

Ans: D Topic: Transition State theory

49. An increase in the kinetic energy of reacting molecules results in: A) a decrease in reaction rate. B) an increase in the probability factor. C) a decrease in the probability factor. D) an increase in the reaction rate. E) no changes.

Ans: D

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Topic: Generalities, leaving group

50. Identify the leaving group in the following reaction. S−Na+

IS

Na+ + I −

A) C6H5S- B) Na+ C) CH3CH2I D) C6H5SCH2CH3 E) I-

Ans: E Topic: Generalities, solvent effects

51. Which is the weakest nucleophile in polar aprotic solvents? A) I- B) Br- C) Cl- D) F- E) All of the above are equally strong nucleophiles, regardless of the type of solvent used

Ans: A Topic: Generalities, solvent effects

52. Which is the weakest nucleophile in polar protic solvents? A) I- B) Br- C) Cl- D) F- E) All of the above are equally strong nucleophiles, regardless of the type of solvent used

Ans: D Topic: Generalities, leaving group

53. Which of the following is the poorest leaving group? A) H− B) CH3O− C) H2O D) OH− E) NH2

− Ans: E

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Topic: Generalities, nucleophiles 54. Which of the following is not a nucleophile?

A) H2O B) CH3O- C) NH3 D) NH4

+ E) All are nucleophiles.

Ans: D Topic: Generalities, solvent effects

55. Which ion is the strongest nucleophile in aqueous solution? A) F- B) Cl- C) Br- D) I- E) All of these are equally strong.

Ans: D Topic: Leaving groups

56. Which of the following is not a good leaving group? A) C2H5O− B) Cl− C) I− D) CH3CO2

− E) All of these are good leaving groups

Ans: A Topic: Leaving groups

57. Identify the leaving group in the following reaction:

CH3OH + CH3OH2 CH3OCH3 + H2OH

A) CH3OH B) CH3OH2

+ C) CH3OCH3 D) H2O E) None of these

Ans: D

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Topic: Nucleophiles

58. Which is the strongest nucleophile? A) OH- B) CH3CH2O- C)

D) CH3CH2OH E) H2O

Ans: B Topic: Nucleophile, solvent effects

59. Which is the most reactive nucleophile in DMF (structure shown below) ?

H

CN

CH3

CH3

O

A) F- B) Cl- C) Br- D) I- E) They are all equally reactive.

Ans: A Topic: Nucleophile, solvent effects

60. Which of these species, acting in a protic solvent, exhibits greater nucleophilic activity than expected on the basis of its basicity?

A) OH- B) CH3O- C) SH- D) Cl- E) H2O

Ans: C

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Topic: Nucleophilicity

61. The relative nucleophilicities of species do not necessarily parallel the relative basicities of the same species because:

A) not all nucleophiles are bases, and vice versa. B) experimental measurements of sufficient accuracy are not available to make the

comparisons. C) nucleophilicity is a thermodynamic matter; basicity is a matter of kinetics. D) basicity is a thermodynamic matter; nucleophilicity is a matter of kinetics. E) Actually, the relative values do parallel one another.

Ans: D Topic: Nucleophiles

62. Ambident nucleophiles are ones which can react with a substrate at either of two nucleophilic sites. Which of the following is not an ambident nucleophile?

:CN: :OH

:O:N::OH

H

I II

VIV

N:O:H

:OCH2CH2S:

III

....

.. ......

.. ....

..

......

2

..

..

A) I B) II C) III D) IV E) V

Ans: B Topic: Nucleophile, solvent effects

63. Which ion is the strongest nucleophile in an aprotic solvent such as dimethylsulfoxide? A) I- B) Br- C) Cl- D) F- E) These are all equal.

Ans: D

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Topic: Leaving group

64. Which of the following is a feasible substitution reaction? A) CH3CH2Cl + NaBr ⎯⎯⎯⎯→ CH3CH2I + NaCl B) CH3CH3 + NaCN ⎯⎯⎯⎯→ CH3CH2CN + NaH C) CH3CH2Cl + NaOH ⎯⎯⎯⎯→ CH2=CH2 + H2O + NaCl D) More than one of the above E) None of the above

Ans: A Topic: Predicting mechanism, products

65. Heating tert-butyl chloride with 1.0 M NaOH in a mixture of water and methanol would yield mainly:

A) (CH3)3COH through an SN1 reaction. B) (CH3)3COCH3 through an SN1 reaction. C) (CH3)3COH through an SN2 reaction. D) (CH3)3COCH3 through an SN2 reaction. E) CH2=C(CH3)2 through an E2 reaction.

Ans: E

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Topic: Free energy diagrams

66. Select the potential energy diagram that represents an exothermic (exergonic) reaction.

A) I B) II C) III D) IV E) V

Ans: E

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Topic: Free energy diagrams

67. Select the potential energy diagram that represents a single-step endothermic (endergonic) reaction.

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Free energy diagrams

68. Select the potential energy diagram that represents a two-step endothermic (endergonic) reaction.

A) I B) II C) III D) IV E) V

Ans: B Topic: Hammond-Leffler postulate

69. The Hammond-Leffler postulate when applied to nucleophilic substitutions and elimination reactions states that:

A) a negatively-charged nucleophile is stronger than its conjugate acid. B) polar aprotic solvents strongly accelerate the rate of SN2 processes. C) bimolecular nucleophilic substitutions are 2nd order kinetically. D) the transition state for an endergonic reaction step (one accompanied by an increase in

free energy) resembles the product of that step. E) elimination reactions will always compete with nucleophilic substitution reactions.

Ans: D

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Topic: Transition state theory

70. Which will be true for any actual or potential nucleophilic substitution reaction? A) ΔH° is positive. B) ΔH° is negative. C) ΔG‡ is positive. D) ΔG° is positive. E) ΔG° is negative.

Ans: C Topic: Entropy changes

71. For the typical SN2 reaction Y- + RX ⎯⎯⎯⎯→ RY + X-

it can be predicted that ΔS‡ will be: A) positive. B) zero. C) negative. D) either positive or negative. E) unpredictable as to algebraic sign.

Ans: C Topic: Free energy changes

72. The reaction, CH3Cl + OH− CH3OH + Cl−

H2O has the following thermodynamic values at 27ºC: ΔH = -75.3 kJ mol-1; ΔS = 54.4 J K-1 mol-1. What is the value of ΔG for this reaction?

A) -73.8 kJ mol-1 B) -76.8 kJ mol-1 C) -59.0 kJ mol-1 D) +91.6 kJ mol-1 E) -91.6 kJ mol-1

Ans: E

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Topic: Activation energy

73. An increase in the temperature at which reaction is carried out increases: A) the collision frequency. B) the fraction of molecules with proper orientation. C) the fraction of molecules with energy greater than Eact. D) More than one of the above E) None of the above

Ans: D Topic: Free energy diagrams

74. The difference in the bond energies of reactants and the transition state of a reaction is designated by the notation:

A) ΔH° B) ΔH‡ C) ΔG° D) ΔG‡ E) ΔS‡

Ans: B Topic: Hammond-Leffler postulate

75. Which is a true statement concerning the transition state of the rate-determining step of an SN1 reaction?

A) Structurally, it closely resembles the carbocation intermediate. B) Both covalent bond-breaking and bond-making are occurring. C) Formation of the transition state is an exothermic reaction. D) Necessarily, the transition state has zero charge overall. E) More than one of the above

Ans: A Topic: Stereochemistry of SN/E reactions

76. Which of the following reactions proceeds with inversion of configuration at the carbon bearing the leaving group?

A) SN2 B) SN1 C) E2 D) E1 E) All of these

Ans: A

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Topic: Predicting mechanism, stereochemistry of SN reactions

77. Consider the substitution reaction that takes place when (R)-3-bromo-3-methylhexane is treated with methanol. Which of the following would be true?

A) The reaction would take place only with inversion of configuration at the stereogenic center.

B) The reaction would take place only with retention of configuration at the stereogenic center.

C) The reaction would take place with racemization. D) No reaction would take place. E) The alkyl halide does not possess a stereogenic center.

Ans: C Topic: Predicting mechanism, stereochemistry of SN reactions

78. Consider the substitution reaction that takes place when (R)-3-bromo-3-methylhexane is treated with sodium methoxide. Which of the following would be true?

A) An SN2 reaction would take place with inversion of configuration at the stereogenic center.

B) An SN1 reaction would take place with retention of configuration at the stereogenic center.

C) An SN1 reaction would take place with racemization of configuration at the stereogenic center.

D) An SN1 reaction would take place, accompanied by an E1 reaction, affording a complex mixture of products.

E) An E2 reaction would take place, during which the stereogenic center is lost. Ans: E

Topic: Predicting mechanism, stereochemistry of SN reactions

79. Consider the substitution reaction that takes place when (R)-3-iodo-3-methylheptane is treated with sodium acetate (CH3CO2Na). Which of the following would be true?

A) An SN2 reaction would take place with inversion of configuration at the stereogenic center.

B) An SN1 reaction would take place with retention of configuration at the stereogenic center.

C) An SN1 reaction would take place with racemization of configuration at the stereogenic center.

D) An SN1 reaction would take place, accompanied by an E1 reaction, affording a complex mixture of products.

E) An E2 reaction would take place, during which the stereogenic center is lost. Ans: D

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Topic: Predicting products

80. Which alkyl halide, when treated with sodium ethoxide in ethanol, would afford a product mixture consisting of more than one elimination product?

A) 1-bromo-3,3-dimethylpentane B) 1-bromo-2,3-dimethylpentane C) 2-bromo-3,4-dimethylpentane D) 2-bromo-3,3-dimethylpentane E) None of the above would yield more than one elimination product

Ans: C Topic: Leaving groups, nucleophiles

81. Which SN2 reaction will occur most rapidly in a mixture of water and ethanol? A) I- + CH3CH2–Br ⎯⎯⎯⎯→ CH3CH2–I + Br- B) I- + CH3CH2–Cl ⎯⎯⎯⎯→ CH3CH2–I + Cl- C) I- + CH3CH2–F ⎯⎯⎯⎯→ CH3CH2–I + F- D) Br- + CH3CH2–Cl ⎯⎯⎯⎯→ CH3CH2–Br + Cl- E) Br- + CH3CH2–F ⎯⎯⎯⎯→ CH3CH2–Br + F-

Ans: A Topic: Predicting mechanism, kinetics

82. Which SN2 reaction will occur most rapidly in aqueous acetone solution? Assume concentrations and temperature are the same in each instance.

A) HO- + CH3-Cl ⎯⎯⎯⎯→ CH3OH + Cl- B) HO- + CH3CH2-Cl ⎯⎯⎯⎯→ CH3CH2OH + Cl- C) HO- + (CH3)2CH-Cl ⎯⎯⎯⎯→ (CH3)2CHOH + Cl- D) HO- + (CH3)3C-Cl ⎯⎯⎯⎯→ (CH3)3COH + Cl- E) HO- + (CH3)3CCH2-Cl ⎯⎯⎯⎯→ (CH3)3CCH2OH + Cl-

Ans: A Topic: Kinetics

83. Which alkyl halide would you expect to undergo an SN2 reaction most slowly? A) 1-bromohexane B) 1-bromo-2-methylpentane C) 1-bromo-3-methylpentane D) 1-bromo-4-methylpentane E) 1-bromo-2,2-dimethylbutane

Ans: E

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Topic: Kinetics, nucleophilicity

84. Which SN2 reaction would take place most rapidly? A)

OH− + CH3Cl CH3OH + Cl−25oCH2O

B)

H3C O−

OH2O25oC H3CO CH3

O

+ CH3Cl + Cl−

C) H2O + CH3Cl CH3OH2

+ + Cl−25oCH2O

D) CH3OH

25oC H3CO

CH3

H

CH3OH + CH3Cl + Cl−

E) SH− + CH3Cl CH3SH + Cl−

25oCH2O

Ans: E Topic: Leaving groups

85. Which nucleophilic substitution reaction would be unlikely to occur? A) HO− + CH3CH2–I ⎯⎯⎯⎯→ CH3CH2–OH + I− B) I− + CH3CH2–H ⎯⎯⎯⎯→ CH3CH2–I + H− C) CH3S− + CH3–Br ⎯⎯⎯⎯→ CH3S–CH3 + Br− D) All of the above would be unlikely to occur E) None of the above would be unlikely to occur

Ans: B Topic: Predicting products

86. Which nucleophilic substitution reaction would be likely to occur (although probably not in excellent yield, due to competing elimination) ?

A) HO− + CH3CH2CH2CHICH3 ⎯⎯⎯⎯→ CH3 CH2CH2CHOHCH3 + I− B) Cl− + CH3CH2CH2CH2–OH ⎯⎯⎯⎯→ CH3CH2CH2CH2–Cl + OH− C) CH3S− + CH3CH2CH2–OCH3 ⎯⎯⎯⎯→ CH3S–CH2CH2CH3 + OCH3

− D) All of the above are likely to occur E) None of the above are likely to occur

Ans: B

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Topic: Leaving groups

87. Which alkyl halide would you expect to react most slowly when heated in aqueous solution?

A) (CH3)3C-F B) (CH3)3C-Cl C) (CH3)3C-Br D) (CH3)3C-I E) They would all react at the same rate.

Ans: A Topic: Nucleophilicity, leaving groups

88. Which SN2 reaction would you expect to take place most rapidly? Assume that the concentrations of the reactants and the temperature are the same in each instance:

A) CH3S− + CH3I CH3SCH3 + I −

B)

H3CS

CH3

H

CH3SH + CH3I + I −

C) CH3O− + CH3I CH3OCH3 + I −

D)

H3CO

CH3

H

CH3OH + CH3I + I −

E) CH3S− + CH3Cl CH3SCH3 + Cl −

Ans: A Topic: Leaving groups

89. Which nucleophilic substitution reaction is not likely to occur? A) I− + CH3CH2–Cl ⎯⎯⎯⎯→ CH3CH2–I + Cl− B) I− + CH3CH2–Br ⎯⎯⎯⎯→ CH3CH2–I + Br− C) I− + CH3CH2–OH ⎯⎯⎯⎯→ CH3CH2–I + OH− D) CH3O− + CH3CH2–Br ⎯⎯⎯⎯→ CH3CH2–OCH3 + Br− E) OH− + CH3CH2–Cl ⎯⎯⎯⎯→ CH3CH2–OH + Cl−

Ans: C

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Topic: Leaving groups

90. Which of the following would be most reactive in an SN2 reaction? A) Br

B)

Br C)

Br D) Br

E)

Br Ans: D

Topic: Steric hindrance

91. Which alkyl chloride, though primary, is essentially unreactive in SN2 reactions? A) Cl

B)

Cl

C)

Cl

D) Cl

E)

Cl

Ans: E

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Topic: Kinetics

92. Which alkyl halide would be most reactive in an SN1 reaction?

Br Br

BrBr

Br

IV V

IIIIII

A) I B) II C) III D) IV E) V

Ans: D Topic: Predicting mechanisms

93. Which of these compounds would give the largest E2/SN2 product ratio on reaction with sodium ethoxide in ethanol at 55°C?

A) Cl

B)

Cl

C)

Cl

D)

Cl E)

Cl

Ans: D

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Topic: Multistep synthesis, acid-base reactions, SN2

94. What final product is likely to be obtained through the following series of reactions?

NaNH2 A Br

NH3(l)B

Ans:

Topic: Multistep synthesis, acid-base reactions, SN2, hydrogenation

95. What final product is likely to be obtained through the following series of reactions?

NaNH2 ACl

NH3(l)

excess H2B C

Ni Ans:

Topic: Multistep synthesis, acid-base reactions, SN2

96. What final product is likely to be obtained through the following series of reactions?

OH NaH

diethyletherA

ClB

Ans: O

SHORT ANSWER QUESTIONS Topic: Bond length, bond strength, leaving groups

97. As we go down Group 7A of the periodic table, the size of the halogen atom increases; accordingly, the carbon-halogen bond length gets _______________ and the bond strength gets _______________. Ans: longer; weaker

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Topic: Transition state theory

98. In the SN2 reaction, the unstable arrangement of atoms in which both the nucleophile and the leaving group are partially bonded to the same carbon atom is called the ______________________. Ans: transition state

Topic: Solvolysis

99. A reaction in which the nucleophile is a molecule of the solvent is referred to as a ______________ reaction. Ans: solvolysis

Topic: Carbocation stability

100. The substitution mechanism whose rate depends primarily on the relative stability of the intermediate carbocation is the _________. Ans: SN1

Topic: Steric hindrance

101. The substitution mechanism whose rate depends primarily on the degree of steric hindrance around the leaving group is the _________. Ans: SN2

Topic: Carbocation stability

102. The stabilizing effect of alkyl substituents on carbocations can be explained through _____________________. Ans: hyperconjugation

Topic: Activation energy, kinetics

103. Increasing the concentration of either of the reactants of an SN2 reaction increases the rate of the reaction. The primary reason for this is that increasing the concentration increases ________________________. Ans: the frequency of collisions between reactant species, thereby statistically

increasing the chance encounters between species having the requisite Eactivation Topic: Activation energy, transition state theory

104. In order for colliding species to react, they must _____________ and ____________. Ans: have energy equal/greater than the activation energy, approach with the proper

orientation.

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Topic: Free energy diagrams

105. Draw the potential energy diagram that represents an exothermic reaction between a tertiary alkyl halide and methanol. Briefly explain your rationale. Ans: The reaction is likely to occur via an SN1 mechanism. The first step is the rate-

determining step, leading to the formation of a tertiary carbocation. The second step is a fast step, where the methanol oxygen acts as a nucleophile, attaching to the positively charged carbon, forming a protonated ether; the last step is a fast loss of a proton to form the (uncharged) ether product.

Energy

time Topic: Predicting reaction mechanisms

106. Give a detailed reaction mechanism for the reaction expected to occur when 2-bromo-2-methylpentane is heated with sodium methoxide. Draw clear structural formulas of all relevant species and use curved arrows to represent electron flow. Also indicate which step is likely to be rate-determining. Ans: The reaction is likely to occur via an E2 mechanism. The first step is the rate-

determining step, leading to the formation of a tertiary carbocation, followed by base promoted elimination to afford 2 different alkene products.

Br H

H

:OCH3

....

..: :

slow

fast[ - Br: ]....

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Topic: SN1 kinetics

107. Typically, increasing the concentration of the nucleophile of an SN1 reaction has no impact on the rate of the reaction. The reason for this is that ________________________. Ans: An SN1 reaction is a multi-step process; the overall reaction rate is determined by

the rate of formation of the carbocation intermediate. Since the nucleophile is not involved in the rate-determining step, changes in its concentration typically have no impact on the rate of reaction.

Topic: Nucleophilicity, solvent effects

108. The relative nucleophilicity of the halide ions in polar aprotic solvents is observed to be markedly different from that in protic solvents. Explain briefly. Ans: The smaller, more highly electronegative fluoride ion is more effectively solvated

in a protic solvent and is therefore a weaker nucleophile compared to the larger, less electronegative and more polarizable iodide ion. The situation is reversed in aprotic solvents, where the nucleophile is essentially unsolvated; thus, the nucleophilicity parallels the basicity of the halide ions, so that the fluoride ion is the strongest nucleophile of the halide ions

Topic: Acid-base reactions, intramolecular SN2

109. When 5-bromo-1-pentanol is treated with sodium hydride in diethyl ether, the product is analyzed to be C5H10O. Propose a likely structure for this product, suggesting a reasonable mechanistic pathway for its formation. Ans: The alcohol is likely to be first deprotonated by the strong base, generating an

alkoxide ion, which can then undergo intramolecular SN2 reaction to afford the observed product, a cyclic ether.

Cl OHNaH

Cl O Na+

−H2

O NaCl....

..

.. :

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MULTIPLE CHOICE QUESTIONS Topic: Nomenclature

1. A correct IUPAC name for the following compound is:

A) 3,3,5-trimethyl-2-hexene B) 3-isobutyl-3-isopropyl-2-propene C) 3-isobutyl-4-methyl-2-pentene D) 3-(1-methylethyl)-5-methyl-2-hexene E) None of the above

Ans: D Topic: Nomenclature

2. The correct IUPAC name for the following compound is: Br

A) 2-Bromo-4-methylenehexane B) 2-(2-Bromopropyl)-1-butene C) 4-Bromo-2-ethyl-1-pentene D) 2-Bromo-4-ethyl-1-pentene E) 2-Bromo-4-ethyl-4-pentene

Ans: C Topic: Nomenclature

3. Give the IUPAC name for

A) 3-Methyl-4-hexyne B) 4-Methyl-2-hexyne C) 2-Ethyl-3-pentyne D) 4-Ethyl-2-pentyne E) 3-Methyl-2-hexyne

Ans: B

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Topic: Nomenclature

4. The correct IUPAC name for the following compound is:

A) 4,5-Dimethyl-3-propyl-2-hexene B) 4,5-Dimethyl-3-propyl-1-hexene C) 3-(2,3-Dimethylpropyl)-1-hexene D) 2,3-Dimethyl-4-isopropyl-5-hexene E) 2,3-Dimethyl-4-propyl-5-hexene

Ans: B Topic: Nomenclature

5. Select the structure of 4–ethyl-2,3-dimethyl-2-heptene. A)

B)

C)

D)

E)

Ans: B

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Topic: Nomenclature

6. Select the structure for cis-3-methyl-6-vinylcyclohexene.

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: B Topic: Nomenclature

7. The correct IUPAC name for the following compound is:

Br

Cl

A) (E)-2-Bromo-3-chloro-5-methyl-2-hexene B) (E)-2-Bromo-3-chloro-5-methyl-3-hexene C) (Z)-2-Bromo-3-chloro-5-methyl-3-hexene D) (Z)-2-Bromo-3-chloro-5-methyl-2-hexene E) (E)-2-Methyl-5-bromo-4-chloro-4-hexene

Ans: A

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Topic: Nomenclature

8. The IUPAC name for diisobutylacetylene is A) 2,7-Dimethyl-4-octene B) 2,7-Dimethyl-4-octyne C) 3,6-Dimethyl-4-octyne D) 2,5-Diethyl-3-hexyne E) 2,2,5,5-Tetramethyl-3-hexyne

Ans: B Topic: Carbocation Stability, Rearrangement

9. Which of the following carbocations would NOT be likely to undergo rearrangement? A) CH3CHCHCH3

CH3 B)

CH3CHCCH3

CH3

CH3

C)

CH3CCH2CH3

CH3

D)

CH3CHCH2

CH3

E)

CH3CCHCH2CH3

CH3

CH3

Ans: C

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Topic: Carbocation stability

10. Which alcohol would initially produce the most stable carbocation when treated with concentrated H2SO4?

A) OH

B)

OH C)

OH D)

HO

E) HO

Ans: A

Topic: Carbocation Stability, Rearrangement

11. Which statement(s) is (are) true of acid-catalyzed alcohol dehydrations? A) Protonation of the alcohol is a fast step. B) Formation of a carbocation from the protonated alcohol is a slow step. C) Rearrangements of less stable carbocations to more stable carbocations are common. D) Loss of a proton by the carbocation is a fast step. E) All of the above

Ans: E Topic: Carbocation Stability, Rearrangement

12. Carbocations are frequent intermediates in acidic reactions of alkenes, alcohols, etc. What do carbocations usually do? They may:

A) rearrange to a more stable carbocation. B) lose a proton to form an alkene. C) combine with a nucleophile. D) react with an alkene to form a larger carbocation. E) do all of the above.

Ans: E

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Topic: Carbocation Stability, Rearrangement

13. Neopentyl alcohol, (CH3)3CCH2OH, cannot be dehydrated to an alkene without rearrangement. What is the chief product of dehydration?

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: B Topic: Carbocation Stability, Rearrangement

14. Rearrangements are likely to occur in which of the following reaction types? A) SN1 reactions B) SN2 reactions C) E1 reactions D) E2 reactions E) Both SN1 and E1 reactions

Ans: E

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Topic: Alkene Synthesis, Reaction Mechanisms

15. Which compound listed below would you expect to be the major product when 2-bromo-2-methylbutane is refluxed with KOH/ethanol?

A) OH

B)

O C)

D)

E)

Ans: D

Topic: Alkene Synthesis, Reaction Mechanisms

16. Which product(s) would be produced by acid-catalyzed dehydration of 2-methyl-2-pentanol?

A)

B) and

C) and

D)

E) O

Ans: B

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Topic: Alkene Synthesis, Reaction Mechanisms

17. Which product (or products) would be formed in appreciable amount(s) when trans-1-bromo-2-methylcyclohexane undergoes dehydrohalogenation upon treatment with sodium ethoxide in ethanol?

I II III IV

A) I B) II C) III D) IV E) More than one of these

Ans: B Topic: Alkene Reactions, Reaction Mechanisms

18. Which would be the major product of the following reaction?

D

CH3

H

D

D

CH3

D

H

CH3

H

D

D

I II

IV V

D

CH3

H

D

III

CH3

D

H

D

D2, Ni?

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Alkene Synthesis, Reaction Mechanisms

19. What is the major product of the reaction,

Br

(CH3)3COK

(CH3)3COHheat

?

A) (CH3)2C=C(CH3)2 B) (CH3)3C–CH=CH2 C) (CH3)2C=CHCH3 D) (CH3)2C=CHCH2CH3 E) None of these

Ans: B Topic: Alkene Synthesis, Reaction Mechanisms

20. Which compound would be the major product? Br (CH3)3COK

(CH3)3COHheat

?

A) O

B)

C)

D) OH

E)

Ans: E

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Topic: Alkene Synthesis, Reaction Mechanisms, Carbocation Rearrangements

21. What will be the major product of the following reaction?

OH

85% H3PO4

heat?

A)

B)

C)

D) O

E)

Ans: A

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Topic: Alkene Synthesis, Reaction Mechanisms, Carbocation Rearrangements

22. Which alkene would you expect to be the major product of the following dehydration?

OH

H2SO4

IV V

III

heat?

I II

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Alkyne Synthesis, Catalytic hydrogenation

23. The structure of the product, C, of the following sequence of reactions would be:

ACH3CH2Br

BH2 C

NH3(l) Ni2B [P-2]

NaNH2

A)

B)

C)

D) Br

E)

Ans: A

Topic: Dissolving Metal Reduction; trans-hydrogenation

24. The structure of the product obtained from 2-butyne and Li/C2H5NH2 is: A)

B)

C)

HN

D)

NH

E)

Ans: A

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Topic: Catalytic hydrogenation

25. Which alkene would yield 3-methylpentane when subjected to catalytic hydrogenation? A) B)

C) D)

E)

Ans: B

Topic: Alkyne Synthesis

26. Which reaction would yield 2-butyne? A) CH3C≡C:− Na+ + CH3Br ⎯⎯⎯⎯→ B) CH3CH2Br + HC≡C:− Na+ ⎯⎯⎯⎯→ C) CH3:− Na+ + HC≡CCH3 ⎯⎯⎯⎯→ D) More than one of these E) None of these

Ans: A Topic: Alkyne Synthesis

27. Which of the following methods could be used to synthesize 4,4-dimethyl-2-hexyne? A)

CCH3

C2H5CH3

C C: Na H3C I

B) H3C C C: Na C

CH3

C2H5CH3

Br

C)

BrBr

NaNH2 ( excess)

NH3 (l)

D) More than one of these E) None of these

Ans: D

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Topic: Alkene Synthesis

28. Your task is to convert 2-bromobutane to 1-butene in highest yield. Which reagents would you use?

A) KOH/H2O B) KOH/CH3OH C) CH3ONa/CH3OH D) CH3CH2ONa/CH3CH2OH E) (CH3)3COK/(CH3)3COH

Ans: E Topic: Alkene Synthesis, Nomenclature

29. Which of the following reactions would yield 3,3-dimethyl-1-butene in a reasonable percentage yield (i.e., greater than 50%)?

A)

OHheat

H2SO4

B)

Brheat

(CH3)3COK, (CH3)3COH

C)

BrBr

i) 3 NaNH2, mineral oil, heat

ii) H3O+

D) All of these E) Answers B) and C) only

Ans: B

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Topic: Alkene Synthesis, Reaction Mechanisms

30. Which compound(s) would be produced by the following reaction?

CH3

Br

H

H3CCH3CH2OH

CH3

OCH2CH3

H

H3C

OCH2CH3

CH3

H

H3C

I II III

CH3

CH3

55oC?

A) I B) II C) III D) More than one of the above E) All of the above

Ans: E Topic: Alkene Synthesis, Nomenclature, Reaction Mechanisms

31. Dehydrohalogenation of tert-pentyl bromide will produce 2-methyl-1-butene as the chief product when:

A) CH3COONa is employed as the base. B) KOH/C2H5OH is employed as the base. C) CH3CH2ONa/CH3CH2OH is employed as the base. D) (CH3)3COK/(CH3)3COH is employed as the base. E) any base is used, as long as the temperature is sufficiently high.

Ans: D Topic: Alkene Synthesis, Nomenclature, Reaction Mechanisms

32. Which is not a satisfactory procedure for the synthesis of 3-methyl-1-butene? A) (CH3)2CHCΗΟΗCH3 + conc. H2SO4 B) (CH3)2CHC≡CH + Li/liq.NH3 C) (CH3)2CHCH2CH2Br + CH3ONa/CH3OH D) (CH3)2CHCHBrCH3 + (CH3)3COK/(CH3)3COH E) (CH3)2CHC≡CH + H2/Ni2B (P-2)

Ans: A

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Topic: Alkene Synthesis, Nomenclature, Reaction Mechanisms

33. Which of these is the most satisfactory method for the preparation of cis-2-pentene? A) CH3CHBrCH2CH2CH3 + (CH3)3COK/(CH3)3COH B) CH3C≡CCH2CH3 + H2,Pt C) CH3C≡CCH2CH3 + H2, Ni2B (P-2) D) CH3C≡CCH2CH3 + Li/liq. NH3 E) CH3CH2CHBrCH2CH3 + CH3CH2ONa/CH3CH2OH

Ans: C Topic: Alkyne Reduction, Nomenclature, Reaction Mechanisms 34. Which of the following reductions of an alkyne is NOT correct?

A) 2-Pentyne + 2H2/Pt pentane B) 2-Pentyne + H2/Ni2B Z-2-Pentene C) 2-Pentyne + Li/NH3(l) Z-2-Pentene D) All of the above are correct. E) None of the above is correct.

Ans: C Topic: Alkene Synthesis, Nomenclature, Reaction Mechanisms

35. Which of the following reactions would yield 2-pentyne? A) I

(1 mol)

NaNH2

B) NaNH2 Br(1 mol)

C) Br

Br

ZnCH3CO2H

D)

OH

HAheat

E) Br

NaOC2H5C2H5OH

Ans: B

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Topic: Alkyne Synthesis, Nomenclature, Reaction Mechanisms

36. Which reaction would not be a method for preparing 5-methyl-1-hexyne? A)

Br1) NaNH2 (2 mol), liq NH3

2) NH4+

B) HC CNa Cl+

C)

Li HC CH+D)

BrBr

1) NaNH2 (3 mol), liq NH3

2) NH4+

E)

Br

Br1) NaNH2 (3 mol), liq NH3

2) NH4+

Ans: C Topic: Index of Hydrogen Deficiency

37. Compute the index of hydrogen deficiency for the molecule C10H8. A) 3 B) 4 C) 5 D) 6 E) 7

Ans: E

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Topic: Index of Hydrogen Deficiency

38. Which compound has an index of hydrogen deficiency equal to three?

I II III

IV V

A) I, III B) IV, V C) V D) II E) II, V

Ans: E Topic: Index of Hydrogen Deficiency, Nomenclature

39. What is the index of hydrogen deficiency of bicyclo[2.2.2]octane? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

40. Which is a possible structure for a compound with an index of hydrogen deficiency equal to 3 and which absorbs one molar equivalent of hydrogen when treated with hydrogen and a platinum catalyst?

I II III IV VA) I B) II C) III D) IV E) V

Ans: C

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Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

41. Upon catalytic hydrogenation, a compound C6H6 absorbs four moles of hydrogen. Select a structure for C6H6.

I II III IV V

A) I, II B) III C) II, III D) IV, V E) I, IV, V

Ans: D Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

42. A compound, C6H10, which reacts with 2 mol of hydrogen over a platinum catalyst and which shows an IR absorption band at approximately 3300 cm-1 could be:

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

43. On hydrogenation, a compound C9H12 absorbs 2 mol of hydrogen. Which of the following is a possible structure for the compound?

IIII II

IV V A) I B) II C) III D) IV E) V

Ans: D Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

44. A compound with the formula C10H14 reacts with excess hydrogen and a catalyst to yield a compound with the formula C10H18. The compound could have:

A) one ring and three double bonds. B) two rings and two double bonds. C) two rings and a triple bond. D) no rings and two double bonds. E) More than one of the above

Ans: E Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

45.

Given:

H2, Pt

25oCX (C8H14) Y (C8H16)

One can conclude that X has:

A) no rings and no double bonds. B) no rings and one double bond. C) one ring and one double bond. D) two rings and no double bonds. E) one triple bond.

Ans: C

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Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

46. What is the structure of a compound with formula C6H10 which has IR absorption at approximately 3300 cm-1 and which can be catalytically reduced with hydrogen to 2-methylpentane?

A)

B) C)

D)

E)

Ans: D

Topic: Index of Hydrogen Deficiency, Catalytic Hydrogenation

47. A compound X with the formula C7H10 undergoes catalytic hydrogenation to produce a compound Y with the formula C7H14. What might be true of X?

A) X might have one triple bond and one ring. B) X might have two double bonds and one ring. C) X might have one double bond and two rings. D) X might have one double bond and one triple bond. E) More than one of the above

Ans: E Topic: Alkene Stability, Heats of Hydrogenation and Combustion

48. Which reaction would you expect to liberate the least heat? A)

+ 9O2 6CO2 + 6H2OB) + 9O2 6CO2 + 6H2O

C) + 9O2 6CO2 + 6H2O

D) + 9O2 6CO2 + 6H2OE) + 9O2 6CO2 + 6H2O

Ans: C

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Topic: Alkene Stability, Heats of Hydrogenation and Combustion

49. One mol of each of the following alkenes is subjected to complete combustion. Which would you expect to liberate the LEAST heat?

A) 1-Pentene B) 2-Pentene C) 2-Methyl-1-butene D) 2-Methyl-2-butene E) 3-Methyl-1-butene

Ans: D Topic: Alkene Stability, Heats of Hydrogenation and Combustion

50. Which molecule would have the lowest heat of hydrogenation?

I II III IV V A) I B) II C) III D) IV E) V

Ans: A Topic: Alkene Stability, Heats of Hydrogenation and Combustion, Nomenclature

51. One mole of each of the following alkenes is subjected to complete combustion. Which would you expect to liberate the most heat?

A) 1-Pentene B) cis-2-Pentene C) 2-Methyl-1-butene D) 2-Methyl-2-butene E) trans-2-Pentene

Ans: A

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Topic: Alkene Stability, Heats of Hydrogenation and Combustion

52. Which reaction would you expect to liberate the most heat? A)

+ 9O2 6CO2 + 6H2OB) + 9O2 6CO2 + 6H2O

C) + 9O2 6CO2 + 6H2O

D) + 9O2 6CO2 + 6H2OE) + 9O2 6CO2 + 6H2O

Ans: C Topic: Alkene Stability, Heats of Hydrogenation and Combustion

53. Heats of hydrogenation data would be useful in comparing the relative stabilities of which of the following substances?

I II III IV V A) I, II, III B) III, IV C) I, II, V D) Heats of hydrogenation data would not be a useful way to compare relative stabilities of

any of the substances E) All of the above substances could effectively be compared using heats of hydrogenation

data Ans: C

Topic: Alkene Stability, Heats of Hydrogenation and Combustion

54. Which alkene would liberate the most heat per mole when subjected to complete combustion?

A) B) C)

D) E)

Ans: A

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Topic: Alkene Stability, Heats of Hydrogenation and Combustion

55. Which alkene would liberate the most heat per mole when subjected to catalytic hydrogenation?

A) B) C)

D) E)

Ans: A Topic: Alkene Stability, Heats of Hydrogenation and Combustion

56. One mole of each of the following alkenes is subjected to complete combustion. Which would liberate the least heat?

I II III IV VA) I B) II C) III D) IV E) V

Ans: D Topic: Alkene Stability, Heats of Hydrogenation and Combustion

57. Which alkene is most stable?

I II III IV V

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Alkene Stability, Heats of Hydrogenation and Combustion

58. Concerning the relative stabilities of alkenes, which is an untrue statement? A) Unless hydrogenation of the alkenes gives the same alkane, heats of hydrogenation

cannot be used to measure their relative stabilities. B) In general, the greater the number of alkyl groups attached to the carbon atoms of the

double bond, the greater the stability of the alkene. C) The greater the quantity of heat liberated on combustion or hydrogenation of an alkene,

the greater its energy content. D) trans-Cycloalkenes are always more stable than the cis-isomers. E) Heats of combustion can be used to measure the relative stabilities of isomeric alkenes,

even though their hydrogenation products are not identical. Ans: D

Topic: Relative Acidity of Alkenes, Alkynes; Acid-Base Chemistry

59. Which of the following correctly lists the compounds in order of decreasing acidity? A) H2O > HC≡CH > NH3 > CH3CH3 B) HC≡CH > H2O > NH3 > CH3CH3 C) CH3CH3 > HC≡CH > NH3 > H2O D) CH3CH3 > HC≡CH > H2O > NH3 E) H2O > NH3 > HC≡CH > CH3CH3

Ans: A Topic: Relative Acidity of Alkenes, Alkynes; Acid-Base Chemistry

60. Select the strongest base. A) OH− B) RC≡C− C) NH2

− D) CH2=CH− E) CH3CH2

− Ans: E

Topic: Relative Acidity of Alkenes, Alkynes; Acid-Base Chemistry

61. Which ion is the weakest base? A) CH3CH2: − B) CH2=CH: − C) HC≡C: − D) NH2

−....

E) OH −..

..

..

Ans: E

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Topic: Relative Acidity of Alkenes, Alkynes; Acid-Base Chemistry

62. In the following hydrocarbon, which hydrogen would have the smallest value for pKa? CH3CH2CH=CHCH2CH2C≡CH

A) CH3CH2CH=CHCH2CH2C CH

B) CH3CH2CH=CHCH2CH2C CH

C) CH3CH2CH=CHCH2CH2C CH

D) CH3CH2CH=CHCH2CH2C CH

E) CH3CH2CH=CHCH2CH2C CH

Ans: E Topic: Relative Acidity of Alkenes, Alkynes; Bond Lengths

63. Which of the following statements is true when ethane, ethene and acetylene are compared with one another?

A) Acetylene is the weakest acid and has the longest C-H bond length. B) Acetylene is the strongest acid and has the shortest C-H bond length. C) Ethane is the strongest acid and has the longest C-H bond length. D) Ethene is the strongest acid and has the shortest C-H bond length. E) Ethene is the weakest acid and has the longest C-H bond length.

Ans: B

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Topic: Alkene Synthesis; Alcohol Dehydration

64. Which one of the following alcohols would dehydrate most rapidly when treated with sulfuric acid?

OH OH OH

OHOH

I II III

IV VA) I B) II C) III D) IV E) V

Ans: B Topic: Alkene Synthesis; Alcohol Dehydration

65. Which mechanistic step in the acid-catalyzed dehydration of 3,3-dimethyl-2-butanol is the rate determining step?

A)

OH+ H3O+

OH2+

+ H2O

Step 1:

B)

OH2+

+ H2O

Step 2:

C) Step 3:

D) Step 4a:

+ H3O++ H2O

E) Step 4b:

+ H3O++ H2O

Ans: B

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Topic: Alkene Synthesis; Alcohol Dehydration

66. Which alcohol would be most easily dehydrated? A)

CH3CH2CCH2CH3

CH3

OH B)

CH3CH2CHCHCH3

CH3

OH C)

CH3CH2CHCH2CH2OH

CH3

D)

HOCH2CHCH2CH2CH3

CH3

E)

CH3CH2CHCH2CH3

CH2OH

Ans: A

Topic: Alkene Synthesis; Alcohol Dehydration

67. Which alcohol would be most easily dehydrated?

VIVOH

OH

II IIIIOHOH OH

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Alkene Structure; Stereochemistry

68. What is the simplest alkene, i.e., the one with the smallest molecular weight, which can exhibit optical activity?

A) 3-methyl-1-pentene B) 3-methyl-2-pentene C) 4-methyl-1-pentene D) 3-methyl-1-butene E) 4-methyl-2-hexene

Ans: A Topic: Alkene Structure; Stereochemistry

69. Determine the total number of stereoisomers which correspond to this general structure:

CH3CHCHCH=CHCH3

Cl

CH3 A) 4 B) 6 C) 8 D) 10 E) 12

Ans: C Topic: Alkene Structure; Stereochemistry

70. Which can exist as cis-trans isomers? A) 1-Pentene B) 3-Hexene C) Cyclopentene D) 2-Methyl-2-butene E) 3-Ethyl-2-pentene

Ans: B Topic: Alkene Structure; Stereochemistry

71. For which of the following is cis-trans isomerism impossible? A) 2-Hexene B) 3-Methyl-2-pentene C) 3-Hexene D) 2-Methyl-2-butene E) 2-Pentene

Ans: D

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Topic: Alkene Structure; Stereochemistry

72. Which of the following compounds can exhibit cis-trans isomerism? A) 1-Pentene B) 2-Pentene C) 2-Methyl-2-pentene D) 3-Methyl-1-pentene E) 1-Hexene

Ans: B Topic: Alkene Structure; Stereochemistry

73. Which of the following compounds can exhibit cis-trans isomerism? I. 1-Pentene II. 2-Pentene III. 2-Methyl-2-pentene IV. 1,2-Dibromoethene V. 1,1-Dichloroethene

A) II, III, IV B) I, III, V C) II, IV D) II, III E) None of these

Ans: C Topic: Alkene Structure; Stereochemistry

74. What is the total number of pentene isomers, including stereoisomers? A) 2 B) 3 C) 4 D) 5 E) 6

Ans: E

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Topic: Nomenclature; Stereochemistry

75. Cis-trans alkenes are often distinguished from each other by examining the spatial orientation of identical groups relative to the double bond. While this often also corresponds to (Z) and (E) descriptions, sometimes it does not. For which of the following alkenes does cis- not equal (Z) or trans not equal (E)?

Cl

Cl

Br

I

Br Br

FF

Cl

Cl

OOH

I II III IV V

A) I B) II C) III D) IV E) V

Ans: C Topic: Nomenclature; Stereochemistry

76. The most specific term used to designate the relationship of cis-3-hexene to trans-3-hexene is:

A) stereoisomers. B) enantiomers. C) diastereomers. D) constitutional isomers. E) conformational isomers.

Ans: C Topic: Nomenclature; Stereochemistry 77. How many stereoisomers can be predicted for 4–ethyl-2,3-dimethyl-2-heptene?

A) 1 B) 2 C) 3 D) 4 E) None of the above

Ans: B

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Topic: General Information, Bonding

78. How many sigma bonds are there in CH2=CH–C≡CH? A) 6 B) 7 C) 8 D) 9 E) 10

Ans: B Topic: General Information, Bonding

79. What characteristic(s) of alkynes would make it difficult to prepare cyclohexyne? A) The requirement for linearity at the triple bond center B) The large electron density between carbons of a triple bond C) The short carbon-carbon triple bond length D) The need that the carbon-carbon triple bond be internal in the chain E) All of these

Ans: A Topic: General Information, Nomenclature

80. The ambiguous name "methylcyclohexene" does not differentiate among this number of compounds (ignoring stereoisomers):

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: B Topic: Alkene Synthesis

81. Zaitsev's rule states that: A) In electrophilic addition of an unsymmetrical reagent to an unsymmetrical alkene, the

more positive portion of the reagent will become attached to the carbon of the double bond bearing the greater number of hydrogen atoms.

B) An equatorial substituent in cyclohexane results in a more stable conformation than if that substituent were axial.

C) E2 reactions occur only if the β-hydrogen and leaving group can assume an anti-periplanar arrangement.

D) When a reaction forms an alkene, and several possibilities exist, the more (or most) stable isomer is the one which predominates.

E) The order of reactivity of alcohols in dehydration reactions is 3º > 2º > 1º. Ans: D

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Topic: Alkene Synthesis

82. Regarding the use of potassium tert-butoxide as a base in E2 reactions, it is incorrect to state that:

A) this base is more effective than ethoxide ion, because it (KO-t-Bu) is the more basic of the two.

B) it tends to give the anti-Zaitsev, i.e., Hofmann, product. C) it is more reactive in dimethyl sulfoxide than it is in tert-butyl alcohol. D) it favors E2 reactions over competing SN2 reactions. E) it will form, predominantly, the more stable alkene.

Ans: E Topic: General Information

83. When an elimination reaction gives the most stable alkene as the major product, we say that the elimination follows ________________'s rule. Ans: Zaitsev

Topic: General Information

84. When an elimination reaction gives the less substituted alkene as the major product, we say that the elimination follows ________________'s rule. Ans: Hofmann

Topic: General Information

85. In a dehydration reaction, the leaving group is _______________. Ans: a molecule of water

Topic: General Information

86. In hydrogenation reactions, both hydrogen atoms add to the pi system from the same face of the molecule. This is an example of a(n) _________ addition. Ans: syn

Topic: General Information

87. Syn hydrogenation of an alkyne will produce a _________ alkene. Ans: Cis / Z

Topic: General Information

88. Dehydration of alcohols requires a __________________ catalyst. Ans: strong acid

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Topic: General Information

89. Carbocations have three options available for further reaction. These options include reaction with a nucleophile, loss of a beta proton to give an alkene, and ________________. Ans: rearrangement

Topic: General Information

90. Alkynes can be produced from either __________________ or _________________ dihalides. Ans: vicinal/geminal

Topic: General Information

91. Conversion of alkynes to E-alkenes (trans-alkenes) can be accomplished via a __________________ reaction. Ans: dissolving metal reduction

Topic: Nomenclature, Bonding

92. The number of (s-sp2) bonds in a molecule of 2,3-dimethyl-2,4-heptadiene is _____. Ans: two

Topic: Alkene Hydrogenation

93. How will you prepare cis-1,2-dimethylcyclohexane from 1,2-dimethylcyclohexene? Ans: Catalytic hydrogenation with H2, Ni (or Pt/Pd)

H2, Ni

Topic: Alkyne Reduction

94. How will you prepare trans-2-heptene from 2-heptyne? Ans: Dissolving metal reduction with metallic Na in NH3(l).

Na, NH3 (l)

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SHORT EXPLANATION / STRUCTURE DRAWING QUESTIONS Topic: Nomenclature, Stereochemistry

95. Draw the structures of all stereoisomers of 2-chloro-4-methyl-3-hexene, clearly showing all stereochemical details, using appropriate 3-D representations (dash-wedge, etc.) as relevant. Ans: 2-chloro-4-methyl-3-hexene

Cl H H Cl Cl H H Cl

(2R, 3E) (2S, 3E) (2R, 3Z) (2S, 3Z) Topic: Alkene Nomenclature, Relative Stability

96. The ambiguous name dimethylcyclopentene does not clearly distinguish between several structures. a) Draw the structures of all constitutional isomers corresponding to this name. b) Indicate which of these is likely to be the most stable, i.e, have the smallest heat of combustion, justifying your rationale briefly. c) Which of these structures represents an achiral molecule? Ans: a)

I II III IV V VI

dimethylcyclopentene

b) Structure I is likely to be the most stable, because it is a tetra-substituted alkene: II, IV and V are tri-substituted; III and VI are di-substituted. c) Structure I is achiral

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Topic: Alkyne Synthesis, Acid-Base reactions

97. Complete the following reaction sequence, providing a brief rationale for your answer.

?

Oi) PCl5ii) 3 NaNH2,

mineral oil, heat

iii) H3O+

Ans: O Cl Cl

(-2HCl)I II

NaH3O+

III

3 NaNH2, mineral oil, heat

:PCl5

Reaction with PCl5 would afford a geminal dihalide I, which would undergo E2 elimination when heated, losing 2 moles of HCl to afford the alkyne III. However, since III is a terminal alkyne, it has a hydrogen atom that is labile in presence of NaNH2; hence, an extra mole equivalent of the base is required to ensure complete reaction and convert all of the initially formed III into the sodium alkynide intermediate, II; this, upon acidification, affords the final alkyne product III.

Topic: Alkyne Synthesis, Alkyne Hydrogenation

98. Complete the following reaction, giving structural details of all intermediates as well as the final product.

?1) NaNH2, NH3 (l)2) CH3CH2CH2Br3) H2, Lindlar catalyst

Ans: NaNH2NH3 (l)

H2Lindlar catalyst

: Na

CH3CH2CH2Br

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Topic: Carbocation Stability, Rearrangement

99. What “new”, more stable, carbocation(s) may be formed when the following carbocation undergoes spontaneous rearrangement?

Ans:

Topic: Nomenclature, Multistep Synthesis 100. Propose a two-step synthetic strategy for the synthesis of 2-methylhexane from 5-

methyl-2-hexanol. Ans: OH

H3O+

heat+

H2Ni

Step 1: Acid-catalyzed dehydration of 5-methyl-2-hexanol to yield an isomeric mixture of 5-methyl-1-hexene and 5-methyl-2-hexene Step 2: Catalytic hydrogenation of the double bond with H2, Ni to yield the desired 2-methylhexane

Topic: Nomenclature, Multistep Synthesis

101. Propose a reasonable synthetic strategy for the synthesis of trans-6-methyl-3-heptene from 4-methyl-1-pentyne. Ans: NaNH2

NH3 (l):Na+

Li, NH3(l)

CH3CH2Br

Step 1: Add NaNH2/NH3(l) to selectively deprotonate the alkyne hydrogen. Step 2: Add ethyl iodide to give 6-methyl-3-pentyne by an SN2 process. Step 3: Add Na(s)/NH3(l) to give the desired trans-alkene by dissolving metal reduction.

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Topic: Carbocation Rearrangement, Alkene Synthesis, Dehydration Mechanism

102. Provide a mechanistic explanation for the formation of the observed products in the following reaction.

OH

H3O+

heat Ans:

OH2+

OH O

H

H

H

O

H

H

[-H2O]

OH2+ O

H

H

O

H

H

H

:

::

:

::

::

:

rearrangement

:

1)

2)

3)

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Topic: Nomenclature, Index of Hydrogen Deficiency, IR Spectroscopy, Catalytic Hydrogenation

103. The IR spectrum of an unknown substance Q, C9H16, is found to have distinct peaks at 3310 cm-1 and 2140 cm-1. Treatment of Q with excess H2 in presence of Raney Ni affords nearly quantitative yields of 2,3-dimethylheptane. Propose a reasonable structure for Q, based on the above information, briefly explaining your rationale. Also give its IUPAC name. Ans:

IR: 2140, 3310 cm-1

excess H2 Ni

2,3-dimethylheptane

Substance Q: 5,6-dimethyl-1-heptyne

The Index of Hydrogen deficiency of Q is 2 (compared with C9H20). The IR data suggests that Q is a terminal alkyne; thus, there must be no rings in its structure. The catalytic hydrogenation data provides further details of the carbon skeleton. Due to the specific substitution pattern in this carbon skeleton, there is only one possible position for a terminal triple bond. Thus, the structure given above is consistent with all of the given information. IUPAC Name: 5,6-dimethyl-1-heptyne

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241

MULTIPLE CHOICE QUESTIONS Topic: Structure Elucidation

1. An alkene adds hydrogen in the presence of a catalyst to give 3,4-dimethylhexane. Ozonolysis of the alkene followed by treatment with zinc and acetic acid gives a single organic product. The structure of the alkene is:

A)

CH3CH=C-CHCH2CH3

CH3

CH3

(cis or trans)

B)

CH3CH2C=CCH3

CH3

CH2CH3

(cis or trans)

C) CH2=CCH2CHCH2CH3

CH3

CH3 D)

CH3CH2CCHCH2CH3

CH2

CH3 E)

CH3CH2CHCHCH=CH2

CH3

CH3

Ans: B

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2. Ozonolysis of compound Z yields the products shown below. What is the structure of Z?

O

H

OI II III

IV V

O O O

Z 2HCH + CH3CCH2CH1) O32) Zn, HOAc

A) I B) II C) III D) IV E) V

Ans: B

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3. Compound C has the molecular formula C7H12. On catalytic hydrogenation, 1 mol of C absorbs 1 mol of hydrogen and yields a compound with the molecular formula C7H14. On ozonolysis and subsequent treatment with zinc and acetic acid, C yields only:

OO

The structure of C is:

I II III

IV VA) I B) II C) III D) IV E) V

Ans: E Topic: Structure Elucidation

4. Compound X has the molecular formula C6H10. X decolorizes bromine in carbon tetrachloride. X also shows IR absorption at about 3300 cm-1. When treated with excess hydrogen and a nickel catalyst, X yields 2-methylpentane. The most likely structure for X is:

A)

B)

C)

D)

E)

Ans: D

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5. An unknown compound, A, has the molecular formula C7H12. On oxidation with hot aqueous potassium permanganate, A yields CH3CH2COOH and (CH3)2CHCOOH. Which of the following structures best represents A?

A)

B)

C)

D)

E)

Ans: C

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6. Determine a possible structure for an alkene, X, formula C9H14, on the basis of the following information: X adds one mole of hydrogen on catalytic hydrogenation. On treatment with hot basic KMnO4 followed by acidification, X yields the following dicarboxylic acid.

OH

OHO

O

A possible structure for X might be:

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: C Topic: Structure Elucidation

7. An optically active compound, Y, with the molecular formula C7H12 gives a positive test with cold dilute KMnO4 and shows IR absorption at about 3300 cm-1. On catalytic hydrogenation, Y yields Z(C7H16) and Z is also optically active. Which is a possible structure for Y?

A) CH3CH2CH2CH2CH2C≡CH B) (CH3)2CHCH2CH2C≡CH C) CH3CH2CH(CH3)CH2C≡CH D) CH3CH2CH(CH3)C≡CCH3 E) CH2=CHCH(CH3)CH2CH=CH2

Ans: C

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8. One mole of an optically active compound, X, with the molecular formula C6H8 reacts with three moles of hydrogen in the presence of a catalyst to yield an optically inactive product that cannot be resolved. X also exhibits IR absorption at approximately 3300 cm-1. Which is a possible structure for X?

A) (E)-4-hexen-1-yne B) (Z)-4-hexen-1-yne C) (E)-2-hexen-4-yne D) 2-methyl-1-penten-3-yne E) 3-methyl-1-penten-4-yne

Ans: E Topic: Structure Elucidation

9. An alkene with the molecular formula C10H18 is treated with ozone and then with zinc and acetic acid. The product isolated from these reactions is:

OO

What is the structure of the alkene?

II III

IV V

I

A) I B) II C) III D) IV E) V

Ans: C

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10. An optically active compound, A, with the molecular formula C7H12 reacts with cold dilute KMnO4 and gives IR absorption at about 3300 cm-1. On catalytic hydrogenation, A is converted to B (C7H16) and B is also optically active. Which is a possible structure for A?

II III

IV V

I

A) I B) II C) III D) IV E) V

Ans: E Topic: Structure Elucidation

11. Which substance would undergo the following reaction?

i. O3ii. Zn, HOAc?

O + H O

H

A) 4-Hexen-1-yne r

B) 3-methyl-1-hexene C) (E)-2-hexene D) (Z)-2-hexene E) 4-methyl-1-hexene

Ans: E

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12. Which alkene would yield only CH3CH2COOH on oxidation with hot alkaline potassium permanganate (followed by acid work-up)?

A) (E)-2-hexene B) (Z)-2-hexene C) 2-methyl-2-pentene D) (E)-3-hexene E) (E)-4-methyl-2-pentene

Ans: D Topic: Structure Elucidation

13. An unknown compound, B, has the molecular formula C7H12. On catalytic hydrogenation 1 mol of B absorbs 2 mol of hydrogen and yields 2-methylhexane. B has significant IR absorption band at about 3300 and 2200 cm-1. Which compound best represents B?

A) 3-methyl-1-hexyne B) 5-methyl-2-hexyne C) 5-methyl-1,3-hexadiene D) 5-methyl-1-hexyne E) 2-methyl-1,5-hexadiene

Ans: D Topic: Structure Elucidation

14. What compound would yield an equimolar mixture of CH3CH2CH2CHO and CH3CHO upon treatment with O3, followed by Zn/HOAc?

A) 1-Hexene B) cis-2-Hexene C) trans-2-Hexene D) More than one of these E) None of these

Ans: D Topic: Structure Elucidation

15. An alkene with the molecular formula C8H16 undergoes ozonolysis to yield a mixture of (CH3)2C=O and (CH3)3CCHO. The alkene is:

A) 2,2-Dimethyl-2-hexene B) 2,3-Dimethyl-2-hexene C) 2,4-Dimethyl-2-hexene D) 2,4,4-Trimethyl-2-pentene E) More than one of the above is a possible answer.

Ans: D

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16. Which of the following would decolorize bromine in carbon tetrachloride and yield a ketone upon reaction with sulfuric acid in the presence of catalytic amounts of HgSO4?

A) CH3CH=CHCH3 B) CH3CH=CH2 C) CH3CH2C≡CH D) CH3CH2CH2CH3 E) All of these would give positive results in each test.

Ans: C Topic: Structure Elucidation

17. Which of these compounds will react with cold concd. H2SO4, as well as Br2 in CCl4 ?

A) CH3CH2CH=CHCH3 B) CH3CH2CH2CH=CH2 C) CH3CH2C≡CCH3 D) (CH3)2CHC≡CH E) All of these

Ans: E Topic: Structure Elucidation

18. Which of the following reagents might serve as the basis for a simple chemical test that would distinguish between pure 1-pentene and pure pentane?

A) Bromine in carbon tetrachloride B) Dilute aqueous potassium permanganate C) Concentrated sulfuric acid D) All of the above E) Answers A) and B) only

Ans: D Topic: Structure Elucidation

19. Which reagent or test could be used to distinguish between 3-pentyne and 1-pentyne? A) Br2/CCl4 B) IR examination C) Concd. H2SO4 D) KMnO4,OH- E) None of these

Ans: B

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20. Which reagent or test could be used to distinguish between 2-methyl-2-pentene and 2-methylpentane?

A) Br2/CCl4 B) KMnO4, OH− C) Concd. H2SO4 D) Two of the above E) All of the above

Ans: E Topic: Structure Elucidation

21. Which of the following could be used to distinguish between 1-octyne and 3-octyne? A) Treatment with 2 mol of HX B) Addition of water C) Reaction with KMnO4 D) Decolorization of bromine in CCl4 E) IR examination

Ans: E Topic: Structure Elucidation

22. A reagent or test that could be used to distinguish between 1-pentene and 1-pentyne would be:

A) Bromine in carbon tetrachloride B) Dilute aqueous potassium permanganate C) CrO3 in H2SO4 D) H2SO4 E) IR examination

Ans: E Topic: Structure Elucidation

23. Which of the following could be used as the basis for a simple test that would distinguish between 1-pentyne and pentane?

A) IR examination B) Br2/CCl4 C) KMnO4/H2O D) Two of these E) All of these

Ans: E

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24. Treating 1-methylcyclohexene with H3O+ would yield primarily which of these?

II III

IV V

I

HO HOHO

HOOH

A) I and V B) II C) III and V D) IV E) I, III and V

Ans: D Topic: Reaction Products

25. What would be the major product of the following reaction? HCl

IV

I

Cl

Cl

II

Cl

V

Cl

III

ClCl

A) I B) II C) III D) IV E) V

Ans: B

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26. Treating 1-methylcyclohexene with HCl would yield primarily which of these?

IV

I

Cl

H3C

ClH3C

Cl

H3C

II

V

Cl

H3CCl

III

A) I B) II C) III D) IV E) V

Ans: C Topic: Reaction Products

27. Which product would you expect from the following reaction?

IV

I

H3O+

II

V

III

OH

OH

OH

OH

H2O

A) I B) II C) III D) IV E) V

Ans: D

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28. The reaction of Br2/CCl4 to cyclohexene would produce the compound(s) represented by structure(s):

I II III

H

Br

HBr

H

H

BrBr

H

H

BrBr

A) I alone B) II alone C) II and III D) III alone E) I , II and II

Ans: C Topic: Reaction Products

29. What product would you expect from addition of deuterium chloride to 2-cyclohexyl-4-methyl-2-pentene?

IV

I II

V

III

D

Cl

Cl

D H

D

Cl

D

Cl

DCl

A) I B) II C) III D) IV E) V

Ans: B

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30. What is the chief product of the reaction of IBr with 2-methyl-2-pentene? A) 2-bromo-3-iodo-2-methylpentane B) 3-bromo-2-iodo-2-methylpentane C) 1-bromo-2-iodo-2-methylpentane D) 2-bromo-1-iodo-2-methylpentane E) All of the above

Ans: A Topic: Reaction Products

31. What is the chief product of the acid-catalyzed hydration of 2,5-dimethyl-2-hexene? A) 2,5-dimethyl-1-hexanol B) 2,5-dimethyl-2-hexanol C) 2,5-dimethyl-3-hexanol D) 2,5-dimethyl-2,3-hexanediol E) 2,5-dimethyl-3,4-hexanediol

Ans: B Topic: Reaction Products

32. What product would result from the following reaction?

IV

I II

OCO2H

K MnO4

OH OHVOH OH

III

OH OH

KMnO4, H2Ocold, dilute ?

A) I B) II C) III D) IV E) V

Ans: C

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33. Acid-catalyzed hydration of 2-methyl-1-butene would yield which of the following? A) (CH3)2C(OH)CH2CH3 B) CH2OHCH(CH3)CH2CH3 C) (CH3)2CHCHOHCH3 D) (CH3)2CHCH2CH2OH E) CH3CH2CH(CH3)CH2OH

Ans: A Topic: Reaction Products

34. Which of these is not formed when cyclopentene reacts with an aqueous solution of bromine?

I II III IV V

OH

Br OH

Br Br

Br Br

Br

OH

OH

A) I B) II C) III D) IV E) V

Ans: E Topic: Reaction Products

35. What would be the major product of the following reaction?

I II III IVOH

Br Br

Br Br

OH Br

Br

V

OH

OH

Br2, H2O?

A) I B) II C) III D) IV E) V

Ans: A

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36. Addition of hydrogen chloride to the following molecule would produce:

Cl

I II III

Cl

Cl

Cl

Cl

Cl

Cl

Cl

Cl

IV V

Cl

Cl

?HCl

A) I and II B) II and III C) I and IV D) V E) All of the above are equally likely to be formed

Ans: A

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37. In addition to the expected major product, which compound may be reasonably anticipated as a by-product in the hydroxylation of R-2-methylcyclohexene with cold alkaline permanganate?

IV

I II

V

III

i. KMnO4, H2O

cold, dilute

ii. H3O+?

H3C H

H3C H

H3C HOH

OH

OH

OO

H3C H

OO

H CH3

O O

H CH3 OH

OH

H

A) I B) II C) III D) IV E) V

Ans: E

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38. Select the structure of the major product formed in the following reaction.

IV

I II

Cl

ClCl

Cl

V

Cl

Cl

III

Cl

Cl

?2 HCl

A) I B) II C) III D) IV E) V

Ans: D Topic: Reaction Products

39. Which of these compounds is not formed when gaseous ethene is bubbled into an aqueous solution of bromine, sodium chloride and sodium nitrate?

A) BrCH2CH2Br B) BrCH2CH2Cl C) BrCH2CH2OH D) ClCH2CH2OH E) BrCH2CH2ONO2

Ans: D

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40. Select the structure of the major product formed in the following reaction.

2 Cl2

IV

I II

Cl

ClCl

Cl

Cl

V

Cl

Cl

III

Cl

Cl

Cl Cl

?

A) I B) II C) III D) IV E) V

Ans: C

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41. Addition of excess HBr to 2-methyl-3-heptyne would produce: 2-methyl-3,3-dichloroheptane 2-methyl-2,3-dichloroheptane I II 2-methyl-4,4-dichloroheptane 2-methyl-3,4-dichloroheptane III IV 2-methyl-3-chloroheptene V

A) I and II B) I and III C) II and IV D) V E) All of the above

Ans: B Topic: Reaction Products

42. What would be the major product of the following reaction? Br2, CCl4

I

CH3

BrBr

C3H7

HH

CH3

BrBr

C3H7

HH

II

CH3

BrH

C3H7

HBr

III

C3H7

BrH

CH3

HBr

IV

?

A) Equal amounts of I and II B) Equal amounts of II and III C) Equal amounts of III and IV D) I and II as major products, III and IV as minor products E) All of the above in equal amounts

Ans: A

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43. What would be the major product of the following reaction? Br2, CCl4

I II III

C2H5

BrBr

C3H7

H3CH

C2H5

BrH

C3H7

H3CBr

C2H5

BrBr

C3H7

CH3

H

IV

C3H7

BrCH3

C2H5

HBr

?

A) Equal amounts of I and II B) Equal amounts of II and III C) Equal amounts of III and IV D) I and II as major products, III and IV as minor products E) All of the above in equal amounts

Ans: A Topic: Reaction Products

44. Hydroxylation of cis-2-pentene with cold alkaline KMnO4 yields

I II III

CH3

OHOH

C2H5

HH

CH3

OHH

C2H5

HHO

CH3

HOHO

C2H5

HH

C2H5

OHH

CH3

HHO

IVA) Equal amounts of I and II B) Equal amounts of II and III C) Equal amounts of III and IV D) I and II as major products, III and IV as minor products E) All of the above in equal amounts

Ans: B

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45. The reaction of BrCl (bromine monochloride) with 1-methylcyclopentene will produce as the predominant product:

I II III

Cl

BrCH3 CH3

BrCl

ClBrCH3

IV

CH3

BrCl

V

CH2Cl

Br

+enantiomer

+enantiomer

+enantiomer

+enantiomer

+enantiomer

A) I B) II C) III D) IV E) V

Ans: D Topic: Reaction Products

46. Reaction of trans-2-hexene with a solution of Br2 in CCl4 produces:

I II III

IV

BrH

BrH

HHBr Br

HBr

HBr

BrH

HBr

HBr

BrH

VA) I and II B) II and V C) III and IV D) IV and V E) V

Ans: C

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47. When either cis- or trans-2-butene is treated with hydrogen chloride in ethanol, the product mixture that results includes:

A) CH3CH2CH2CH2Cl B) CH3CH2CH2CH2OCH2CH3 C) CH3CH2CH(CH3)OCH2CH3 D) (CH3)3CCl E) (CH3)2CHCH2OCH2CH3

Ans: C Topic: Reaction Products

48. What is the major product of the following reaction? H2SO4, H2O HgSO4

IV

I II

OH

O

V

O

III

?

OH

OH

OH

A) I B) II C) III D) IV E) V

Ans: D Topic: Reaction Products

49. Addition of 2 mol of HCl to 1-butyne would yield: A) CH3CH2CH2CHCl2 B) CH3CH2CCl2CH3 C) CH3CH2CHClCH2Cl D) CH3CH2CH=CHCl E) CH3CHClCHClCH3

Ans: B

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50. Consider the addition of HCl to 3-methyl-1-butene. The major product of the reaction would be:

A) 1-Chloro-2-methylbutane B) 1-Chloro-3-methylbutane C) 2-Chloro-2-methylbutane D) 2-Chloro-3-methylbutane E) 1-Chloropentane

Ans: C Topic: Reaction Products

51. What is the final product of the following synthesis?

C4H8

HO

HH

OHCH3

CH3

HO

HHO

HCH3

CH3

HO

OHH

HCH3

CH3

I II III

Final Product

H

HHO

OHCH3

CH3

IV

H2Ni2B (P-2)

i. OsO4ii. NaHSO4

2-Butyne

A) I B) II C) III D) IV E) An equimolar mixture of III and IV

Ans: B Topic: Synthetic Strategy

52. A synthetic strategy for converting trans-2-butene into pure cis-2-butene would consist of which of the following?

A) Reaction with H2, Ni2B (P-2) B) Reaction with i) Br2, CCl4; ii) 2 NaNH2, NH3(l); iii) Na, NH3 (l) C) Reaction with H3O+, heat D) Reaction with i) Br2, CCl4; ii) 2 NaNH2, NH3(l); iii) H2, Ni2B (P-2) E) None of these will successfully effect the desired transformation

Ans: D

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53. Which reagent(s) given below could be used to synthesize cis-1,2-cycloheptanediol from cycloheptene?

A) KMnO4, OH−, 5oC B) KMnO4, H3O+, 75oC C) H2SO4, heat D) All of these E) None of these

Ans: A Topic: Synthetic Strategy

54. Which reaction sequence would convert cis-2-butene to trans-2-butene? A) Br2/CCl4; then 2 NaNH2; then H2/Ni2B(P-2) B) Br2/CCl4; then 2 NaNH2; then Li/liq. NH3 C) H3O+, heat; then cold dilute KMnO4 D) HBr; then NaNH2; then H2, Pt E) None of these

Ans: B Topic: Synthetic Strategy

55. The conversion of ethylene to vinyl bromide can be accomplished by use of these reagents in the order indicated.

A) (1) HBr; (2) NaOC2H5 B) (1) Br2; (2) NaOC2H5 C) (1) Br2; (2) H2O D) (1) NaNH2; (2) HBr E) (1) HBr; (2) H2SO4

Ans: B Topic: Synthetic Strategy

56. Cyclohexene is treated with cold dilute alkaline KMnO4. Assuming syn addition, the spatial arrangement of the two hydroxyl groups in the product would be:

A) equatorial-axial B) axial-axial C) equatorial-equatorial D) coplanar E) trans

Ans: A

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57. Which of the following reactions of cyclobutene would yield a meso product? A) Reaction with H3O+, H2O B) Reaction with Br2, CCl4 C) Reaction with Cl2, CCl4 D) Reaction with D2, Pt E) Reaction with hot, alkaline KMnO4, followed by acid workup

Ans: E Topic: Reaction Products

58. How many compounds are possible from the addition of bromine to CH2=CHCH2CH3 (counting stereoisomers separately)?

A) One B) Two C) Three D) Four E) Five

Ans: B Topic: Reaction Products

59. Which alkene would react with cold dilute alkaline permanganate solution to form an optically inactive and irresolvable product?

A)

B)

C)

D)

E)

Ans: C

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60. Which reaction of an alkene proceeds with anti addition? A) Hydroboration/oxidation B) Bromination C) Oxidation with cold KMnO4 D) Hydrogenation E) Oxymercuration-demercuration

Ans: B Topic: Reaction Products

61. A pair of enantiomers results from which of these reactions? A) cyclopentene + cold, dil. KMnO4 ⎯⎯⎯⎯→ B) trans-2-butene + Br2 ⎯⎯⎯⎯→ C) 1-pentene + HCl ⎯⎯⎯⎯→ D) cis-2-butene + D2/Pt ⎯⎯⎯⎯→ E) cyclobutene + OsO4, then Na2SO3 ⎯⎯⎯⎯→

Ans: C Topic: Reaction Products

62. Which reaction would yield a racemic product? A) cyclopentene + D2/Pt ⎯⎯⎯⎯→ B) Cyclopentene + OsO4, then Na2SO3 ⎯⎯⎯⎯→ C) cyclopentene + Br2/H2O ⎯⎯⎯⎯→ D) Cyclopentene + cold, dilute KMnO4 ⎯⎯⎯⎯→ E) Cyclopentene + dilute H2SO4 ⎯⎯⎯⎯→

Ans: C Topic: Reaction Products

63. 3,3-dimethylcyclohexene is subjected to reaction with cold, dilute KMnO4, to give 3,3-dimethyl-1,2-cyclohexanediol. In the most stable conformation of the product, the hydroxyl groups would be:

A) both axial B) both equatorial C) axial-equatorial D) coplanar E) None of these

Ans: B

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64. Cyclohexene reacts with bromine to yield 1,2-dibromocyclohexane. Molecules of the product would:

A) be a racemic form and, in their most stable conformation, they would have both bromine atoms equatorial.

B) be a racemic form and, in their most stable conformation, they would have one bromine atom equatorial and one axial.

C) be a meso compound and, in its most stable conformation, it would have both bromine atoms equatorial.

D) be a meso compound and, in its most stable conformation, it would have one bromine atom equatorial and one axial.

E) be a pair of diastereomers and, in their most stable conformation, one would have the bromines equatorial and axial, and the other would have the bromines equatorial and equatorial. Ans: A

Topic: Reaction Products

65. Which reaction would yield a meso compound? A) Br2/CCl4cis-2-ButeneB)

cis-2-ButeneH2/Pd

C) cis-2-Butene i) OsO4 ii) NaHSO3

D) dil KMnO4

5oCtrans-2-Butene

E) None of these Ans: C

Topic: Reaction Products

66. Which reaction would give a meso compound as the product? A) Cyclopentene + Br2/CCl4 B) Cyclopentene + OsO4, then NaHSO3 C) Cyclopentene + RCO3H, then H3O+ D) Cyclopentene + Cl2, H2O E) More than one of these

Ans: B

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67. Which of the following reactions would yield the final product as a racemic form? A) Cyclohexene + a peroxy acid, then H3O+ B) Cyclohexene + cold, dilute KMnO4 and OH- C) Cyclohexene + HCl D) Cyclohexene + OsO4, then NaHSO3 E) Cyclohexene + D2/Pt

Ans: A Topic: Reaction Products

68. (R)-3-Chloro-1-butene reacts with HCl by Markovnikov addition, and the products are separated by gas chromatography. How many total fractions would be obtained and how many would be optically active?

A) One optically active fraction only B) One optically active fraction and one optically inactive C) Two optically active fractions D) One optically active fraction and two optically inactive E) Two optically active fractions and one optically inactive

Ans: B Topic: Reaction Products

69. The interaction of the π bond of an alkene with an electrophile can initially result in the formation of a species termed a π complex. Which of these cannot combine with an alkene to form a π complex?

A) H+ B) NH3 C) Ag+ D) Hg2+ E) BF3

Ans: B Topic: Reaction Products

70. Markovnikov addition of HI to 2-methyl-2-butene involves: A) initial attack by an iodide ion. B) initial attack by an iodine atom. C) isomerization of 2-iodo-2-methylbutene. D) formation of a carbocation at C-2. E) formation of carbocation at C-3.

Ans: D

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71. Which reaction is NOT stereospecific?

Br2/CCl4trans-2-Butene cis-2-Pentene

trans-2-Hexenedil KMnO4

5oC2-Methyl-2-heptene

1-MethylcyclohexeneH2/Pd

Br2/H2O

HBr

I II

VIV

III

A) I B) II C) III D) IV E) V

Ans: E

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72. Which reaction is regioselective?

D2/Ni

ClI

Br

Br

OH

OHH

H

DD

IClI

II

III

IV

KMnO4

Br2

A) I B) II C) III D) IV E) None of these

Ans: A Topic: General Information

73. The thermodynamic parameters at 298 K for the following reaction are given below.

CH2=CH2 + HClgas phase

CH3CH2Cl ΔHº = -64.9 kJ mol-1 ΔSº = -131 J K-1 mol-1 ΔGº = -25.8 kJ mol-1 Which of the following statements is true of the reaction?

A) Both ΔHº and ΔSº favor product formation. B) Neither ΔHº nor ΔSº favors product formation. C) The entropy term is unfavorable but the formation of ethyl chloride is favored. D) The entropy term is favorable but the formation of ethyl chloride is not favored. E) The sign of ΔGº indicates that the reaction cannot occur as written.

Ans: C

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74. In general, when the addition of an unsymmetrical electrophilic reagent to an unsymmetrical alkene forms the product predicted by Markovnikov's rule, that occurs because:

A) the product is statistically favored. B) steric hindrance favors its formation. C) it is formed via the more/most stable carbocation. D) it is the more/most stable product. E) All of the above are reasons.

Ans: C Topic: General Information

75. Which of these compounds belongs to the class of substances commonly known as "halohydrins"?

A) BrCH2CH2Cl B) ClCH2CO2H C) ICH2CH2OH D) FCH2CH2NH2 E) HOCH2 COCl

Ans: C Topic: General Information

76. Which alkene would you expect to be most reactive toward acid-catalyzed hydration? A) 1 pentene B) trans-2-pentene C) cis-2-pentene D) 2-methyl-1butene E) All of these would be equally reactive.

Ans: D Topic: General Information

77. The most resistant compound to the action of hot alkaline KMnO4 is: A) Pentane B) 1-Pentene C) 2-Pentene D) 2-Pentyne E) Cyclopentene

Ans: A

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78. 2-Pentyne will not react with: A) H2, Pt B) Br2 C) NH3 D) H2SO4 E) KMnO4/H2O

Ans: C Topic: General Information

79. Consider the ozonolysis products obtained from all the unbranched and unsymmetrical isomers of heptene. The reaction product in each case would consist of:

A) a single aldehyde. B) an aldehyde and a ketone. C) two different ketones. D) two different aldehydes. E) a single ketone.

Ans: D SHORT ANSWER QUESTIONS Topic: General Information

80. The rule that correctly predicts the regiochemistry of most ionic additions to alkenes is called ____________________. Ans: Markovnikov's Rule

Topic: General Information

81. When a reaction that could potentially yield two or more constitutional isomers instead produces only one as the major product, the reaction is said to be _____________________. Ans: regioselective

Topic: General Information

82. When a particular stereoisomer reacts in such a way that it gives a particular stereoisomer as a product, even if more than one stereoisomer is theoretically possible, the reaction is said to be _____________. Ans: stereospecific

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83. A reaction in which the reactant is not necessarily chiral but still produces primarily one stereoisomeric form of the product (or a specific subset of the possible stereoisomers) is referred to as a _________________ reaction. Ans: stereoselective

Topic: General Information

84. Hydroboration-oxidation is a reaction with _________ stereochemistry and ________________ regiochemistry. Ans: syn, anti-Markovnikov

Topic: General Information

85. Even when one or more stereogenic centers are produced as the result of an addition reaction to an alkene, the product is always formed as a racemic mixture. Why is that? Ans: Because alkenes are planar, and the reagent can add from either face.

Topic: General Information

86. The “decolorization” of molecular bromine is often used as a functional group test to detect the presence of ________________. Ans: carbon-carbon multiple bonds; or, alkenes and alkynes

Topic: General Information

87. Neutral divalent carbon compounds are called ___________. Ans: carbenes

Topic: General Information

88. Carbenes are frequently produced by α-elimination reactions. These are reactions in which the proton being lost and the leaving group are ___________. Ans: both attached to the same carbon

Topic: General Information

89. π bonds are quite susceptible to reaction with electron-seeking reagents, also referred to as ____________________.

Ans: electrophiles

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90. Predict the final product(s) obtained when (2R,3R)-2-bromo-3-methylpentane is subjected to the following sequence of reactions, briefly explaining your rationale. Provide regiochemical and stereochemical details as relevant.

i) NaOC2H5/C2H5OH, heat ii) BH3, THF iii) H2O2, OH−

Ans: Br

H3C

H

H

NaOC2H5C2H5OH (E2: anti elimination)(2R,3R)

H

CH3

E-3-methyl-2-hexene

H

H3C

OH

H

HO

H

H

CH3

+

Hydroboration/oxidation: overall Anti-Markovnikov, syn addition of H2O

(2S,3R) (2R,3S)3-methyl-2-pentanol

Heating with sodium ethoxide results in E2 elimination; the anti- elimination leads to the formation of E-3-methyl-2-hexene as the major product. Subsequent hydroboration oxidation is regioselective (anti-Markovnikov) and stereospecific (syn), resulting in the formation of racemic (2S,3R & 2R,3S) 3-methyl-2-pentanol. The other diastereomer pair (2S,3S & 2R,3R) is not expected to be obtained.

Topic: Reaction Products

91. Provide a mechanistic explanation for the following observation: The same major product is obtained when 2-ethyl-1-hexene and 3-methyl-2-heptene are allowed to react with HCl.

Ans: HCl

ClHCl

most stable carbocation

Both alkenes are unsymmetrically substituted: the major product is a consequence of regioselective addition to the double bond. Upon reaction with HCl, electrophilic addition of a proton results in the formation of the most stable intermediate carbocation, which then reacts with Cl−, to give the observed product.

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92. Predict the major product(s) of the following reaction, giving regiochemical and/or stereochemical details as relevant.

Br2, H2O?

Ans:

HBrOH

HBrOH+

The reaction takes place with Markovnikov regioselectivity and anti stereospecificity, giving a racemic mixture of the halohydrin as the major product.

Topic: Reaction Products

93. Draw Fischer projection formula(s) of the major product(s) of the reaction between Z-2-methyl-3-hexene and cold, alkaline KMnO4.

Ans: CH(CH3)2

OHOH

C2H5

HH

CH(CH3)2

HOHO

C2H5

HH

cold, dil KMnO4

+

The reaction takes place with syn stereospecificity, giving a racemic mixture of the diol product.

Topic: Reaction Products

94. Draw Fischer projection formula(s) of the major product(s) of the reaction between Z-3-methyl-3-hexene and cold, alkaline KMnO4.

Ans: CH2CH3

OHOH

C2H5

H3CH

CH2CH3

HOHO

C2H5

CH3

Hcold, dil KMnO4

+

The reaction takes place with syn stereospecificity, giving a racemic mixture of the diol product.

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95. Draw Fischer projection formulas of the major product of the reaction between E-2-methyl-3-hexene and aqueous Br2.

Ans: CH(CH3)2HBr

C2H5

HOH

CH(CH3)2

HBr

C2H5

OHH

CH(CH3)2

BrH

C2H5

HHO

CH(CH3)2

BrH

C2H5

HOH+ ++

Br2 H2O

The reaction takes place with anti stereospecificity. Since the alkene is symmetrically substituted, Markovnikov rule is not applicable, and the reaction is not regioselective. The product mixture would therefore consist of 2 pairs of enantiomers, that are constitutional isomers of each other.

Topic: Reaction Products

96. Give a mechanistic explanation for the formation of the following product in significant yield. What other product(s) might also be obtained? Explain clearly.

HI I

Ans: H+ + +fast I−

+

I

II−

The regioselective addition of a proton first generates a secondary carbocation, which can undergo rearrangement to a more stable 3o carbocation by two alternate pathways. One pathway results in ring expansion to a more stable 5-membered ring. This pathway is thus more likely, which would then lead to the observed product. The other pathway is less likely, since ring strain is not relieved; however, this could lead to a minor product, as shown above.

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Topic: Structure Elucidation

97. Deduce the structure of an unknown compound A, C8H16, from the following data. Briefly, but clearly explain your rationale. A decolorizes Br2/CCl4, and upon reaction with excess H2/Ni, affords 1-ethyl-2-methylcyclopentane. When A is subjected to ozonolysis, the following product is obtained.

OO

Ans: A must be 3-ethyl-4-methylcyclopentene. This given data can be explained as shown below:

O

O

OO

decolorizes Br2,CCl4: A must contain pi bonds

H2, Ni

ozonolysis

C8H14: Index of Hydrogen Deficiency of A = 2

A must contain some the same carbon skeleton and one pi bond

pi bond position in A deduced from the structure of the ozonolysis product

A

Topic: Reaction Products

98. Predict the product(s) of the oxidation of 2,3,4-trimethyl-1,5-heptadiene with hot, alkaline KMnO4.

Ans: O

O

OH O

OH+CO2 + H2O +hot, alkaline

KMnO4

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99. Predict the structure of product obtained when cis-2-hexene is allowed to react with Zn/CH2I2. Ans:

Zn, CH2I2H

H

H

H

+

The Zn/CH2I2 produces a carbene which reacts with the alkene to give the corresponding cyclopropane derivative. The reaction proceeds with retention of alkene stereochemistry, resulting in a racemic mixture of the two cis enantiomers.

Topic: Reaction Products

100. Predict the structure of product obtained when 1-hexyne is allowed to react with aqueous H2SO4 in the presence of catalytic amounts of HgSO4.

Ans: HgSO4, H2SO4, H2O OH O

The reaction of 1-hexyne with aqueous H2SO4, in the presence of catalytic amounts of HgSO4, results in regioselective hydration to produce an enol, which tautomerizes to the more stable keto form.

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MULTIPLE CHOICE QUESTIONS Topic: Proton NMR- Chemical Shift, Splitting, Etc.

1. If all the protons of 1-fluoropentane could be discerned, which would you expect to be at the lowest field in the 1H NMR spectrum of this compound?

V IV III

CH3CH2CH2CH2CH2F

II I A) Protons on carbon I B) Protons on carbon II C) Protons on carbon III D) Protons on carbon IV E) Protons on carbon V

Ans: A Topic: Proton NMR- Chemical Shift, Splitting, Etc.

2. Which proton(s) of the compound below would appear as a septet in the 1H NMR spectrum?

V IV III

CH3CH2CH2-O-CHI

III

CH3

CH3

A) The protons on carbon I B) The proton on carbon II C) The protons on carbon III D) The protons on carbon IV E) The protons on carbon V

Ans: B

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Topic: Proton NMR- Chemical Shift, Splitting, Etc.

3. Which proton(s) of the compound below would appear as a doublet in the 1H NMR spectrum?

V IV III

CH3CH2CH2-O-CHI

III

CH3

CH3

A) The protons on carbon I B) The protons on carbon II C) The protons on carbon III D) The protons on carbon IV E) The protons on carbon V

Ans: A Topic: Proton NMR- Chemical Shift, Splitting, Etc.

4. Which proton(s) of the compound below would appear as a triplet in the 1H NMR spectrum?

V IV III

CH3CH2CH2-O-CHI

III

CH3

CH3

A) The protons on carbon II B) The protons on carbon I and V C) The protons on carbon III and V D) The protons on carbon III and IV E) The protons on carbon V

Ans: C Topic: Proton NMR- Chemical Shift, Splitting, Etc.

5. How many signals would you expect to find in the 1H NMR spectrum of CH3OCH2CH2OCH3?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B

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6. Predict the splitting pattern you would observe for the proton at C3 of 2,3-dimethyl-2-phenylbutane.

A) Doublet B) Singlet C) Quartet D) Septet E) Octet

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

7. Predict the splitting pattern you would observe for the proton at C1 of 2,3-dimethyl-2-phenylbutane.

A) Doublet B) Singlet C) Quartet D) Septet E) Octet

Ans: B Topic: Proton NMR- Chemical Shift, Splitting, Etc.

8. Predict the splitting pattern you would observe for the proton at C4 of 2,3-dimethyl-2-phenylbutane.

A) Doublet B) Singlet C) Quartet D) Septet E) Octet

Ans: A

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9. What feature would you expect to see in the 1H NMR spectrum of B after subjecting A to the following reaction?

Cl2

A B

heat or light C8H9Cl + HCl(chief product)

A) There would be only 4 aromatic protons at low field. B) The signal for the protons on the benzylic carbon would be a doublet. C) The signal for the methyl protons would be a triplet. D) The signal for the methyl protons would be a doublet. E) The signal for the methyl protons would integrate for only 2 hydrogens.

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

10. How many 1H NMR signals would trans-1,2-dichlorocyclopropane give? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B Topic: Proton NMR- Chemical Shift, Splitting, Etc.

11. How many 1H NMR signals would the following compound give? ClCH2CHCH3

BrA) 1 B) 2 C) 3 D) 4 E) 5

Ans: D

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12. How many 1H NMR signals would cis-1,2-dichlorocyclopropane give? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C Topic: Proton NMR- Chemical Shift, Splitting, Etc. 13. How many 1H NMR signals would you expect from this compound?

OCH3

OCH3 A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B Topic: Proton NMR- Chemical Shift, Splitting, Etc.

14. The 1H NMR signal for which of the indicated protons occurs furthest downfield?

H C C C

H

Cl

C

H

CH3I

IIIV

V

III

A) I B) II C) III D) IV E) V

Ans: E

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15. The 1H NMR spectrum of which of the compounds below, all of formula C7H12O2, would consist of two singlets only?

OO

I

OO

II

O O

IIIO

O

IV

OO

V A) I B) II C) III D) IV E) V

Ans: E Topic: Proton NMR- Chemical Shift, Splitting, Etc.

16. The 1H NMR spectrum of which of the compounds below, all of formula C7H12O2, would consist of three singlets only?

OO

I

OO

II

O O

IIIO

O

IV

OO

V A) I B) II C) III D) IV E) V

Ans: B

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17. The 1H NMR spectrum of which of the compounds below, all of formula C7H12O2, would consist of a singlet, a doublet and a triplet only?

OO

I

OO

II

O O

IIIO

O

IV

OO

V A) I B) II C) III D) IV E) V

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

18. The 1H NMR spectrum of which of these compounds would consist of a triplet, singlet and quartet only?

A) 2-chloro-4-methylpentane B) 3-chloro-2-methylpentane C) 3-chloropentane D) 1-chloro-2,2-dimethylbutane E) 3-chloro-3-methylpentane

Ans: E Topic: Proton NMR- Chemical Shift, Splitting, Etc.

19. In NMR terminology, protons Ha and Hb are said to be: H Cl

HaHb A) Identical B) Enantiotopic C) Diastereotopic D) Homotopic E) Mesotopic

Ans: C

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20. Consider the 1H NMR spectrum of very pure 1-propanol. Assuming the maximum multiplicity of signals and non-superposition of peaks, what is the expected signal splitting pattern for each signal, in the order (a, b, c, d) ?

CH3-CH2-CH2-OH a b c d

A) 3, 6, 4, 1 B) 3, 6, 4, 3 C) 3, 12, 3, 1 D) 3, 12, 3, 3 E) 3, 12, 6, 3

Ans: C Topic: Proton NMR- Chemical Shift, Splitting, Etc.

21. In the structure shown, Hb and Hc are classified as:

Hb

Ha

Hc A) homotopic protons. B) vicinal protons. C) enantiotopic protons. D) diastereotopic protons. E) isomeric protons.

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

22. In the structure shown, Hb and Hc are classified as:

HaHb

A) homotopic protons. B) vicinal protons. C) enantiotopic protons. D) diastereotopic protons. E) isomeric protons.

Ans: C

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23. In the structure shown, Hb and Hc are classified as:

Hb

Ha

A) homotopic protons. B) vicinal protons. C) enantiotopic protons. D) diastereotopic protons. E) isomeric protons.

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

24. In the structure shown, Hb and Hc are classified as:

HO H

Ha Hb A) homotopic protons. B) vicinal protons. C) enantiotopic protons. D) diastereotopic protons. E) isomeric protons.

Ans: D Topic: Proton NMR- Chemical Shift, Splitting, Etc.

25. Distinction between the methine protons in the compounds I and II below should be possible in the 1H NMR spectra if:

Cl

C2H5H3C

H

I

Cl

H

C2H5H3C

II

A) a very high field instrument is used. B) the spectra are determined in a chiral solvent. C) a long scan time is used for each compound. D) a high amplitude setting is employed. E) Distinction between the enantiomers is impossible.

Ans: B

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Topic: Proton NMR- Unknown Identification.

26. A compound with the molecular formula C4H10O gives a 1H NMR spectrum consisting only of a quartet centered at δ 3.5 and a triplet at δ 1.1. The most likely structure for the compound is:

A)

CH3COH

CH3

CH3

B)

CH3OCHOH

CH3

C) CH3CH2CH2CH2OH D) CH3CH2OCH2CH3 E) CH3CHCH2OH

CH3

Ans: D Topic: Proton NMR- Unknown Identification.

27. Determine the most likely structure of a compound, with the molecular formula C9H12, which gave a 1H NMR spectrum consisting of: a doublet at δ 1.25 a septet at δ 2.90 and a multiplet at δ 7.25

I II III IV V]

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Proton NMR- Unknown Identification.

28. A compound with the molecular formula C10H13Cl gave the following 1H NMR spectrum: singlet, δ 1.6 singlet, δ 3.1 multiplet, δ 7.2 (5H) The most likely structure for the compound is:

Cl Cl Cl

Cl

ClI II III

IV VA) I B) II C) III D) IV E) V

Ans: B Topic: Proton NMR- Unknown Identification.

29. A compound with the molecular formula C8H9BrO gave the following 1H NMR spectrum: triplet, δ 1.4 quartet, δ 3.9 multiplet, δ 7.0 (4H) There was no evidence of an -OH band in the IR spectrum. A possible structure for the compound is:

OBr

I

O Br

II

O

BrIII

O

Br

IV

Br

OV

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Proton NMR- Unknown Identification

30. A compound with the molecular formula C6H15N gave the following 1H NMR spectrum: triplet, δ 0.90 quartet, δ 2.4 There were no other signals. The most likely structure for the compound is:

A) CH3NCH2CH3

CH2CH2CH3

B) CH3NCH2CH2CH2CH3

CH3

C) CH3CH2CH2CH2CH2CH2NH2 D) CH3CH2NCH2CH3

CH2CH3

E) CH3CH2CH2NCH2CH2CH3

H

Ans: D Topic: Proton NMR- Unknown Identification

31. A compound with the molecular formula C8H9ClO gave the following 1H NMR spectrum: triplet, δ 3.7 triplet, δ 4.2 multiplet, δ 7.1 There was no evidence of an -OH band in the IR spectrum. The most likely structure for the compound is:

OCl

I

OCl

II

O

ClIII

O

Cl

IV

Cl

OV

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Proton NMR- Unknown Identification

32. A compound with the molecular formula C3H6Cl2 gave a 1H NMR spectrum consisting only of a triplet centered at δ 3.7 and a quintet centered at δ 2.2. The most likely structure for the compound is:

A) CH3CH2CHCl2 B) CH3CHClCH2Cl C) ClCH2CHClCH3 D) ClCH2CH2CH2Cl E) CH3CCl2CH3

Ans: D Topic: Proton NMR- Unknown Identification

33. A compound with the molecular formula C10H14 gave the following 1H NMR spectrum: doublet, δ 1.2 singlet, δ 2.3 septet, δ 2.8 multiplet, δ 7.1 A possible structure for the compound is:

I II III

IV VA) I B) II C) III D) IV E) V

Ans: B

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Topic: Proton NMR- Unknown Identification

34. A compound C5H10O gave the following spectral data: 1H NMR spectrum IR spectrum, doublet, δ 1.10 strong peak singlet, δ 2.10 near 1720 cm-1

septet, δ 2.50 Which is a reasonable structure for the compound?

II

O

III

O

IV

O

V

O

I

O

A) I B) II C) III D) IV E) V

Ans: E Topic: Proton NMR- Unknown Identification

35. A compound C4H9Br gave the following 1H NMR spectrum: multiplet, δ 4.1 (1H); multiplet, δ 1.8; doublet, δ 1.7; triplet, δ 1.0 (3H) Which is a reasonable structure for the compound?

A) CH3CH2CHBrCH3 B) CH3CH2CH2CH2Br C) (CH3)2CHCH2Br D) (CH3)3CBr

Ans: A

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36. Determine the likely structure for a compound A (C6H10O), which is found to decolorize bromine in carbon tetrachloride. Its spectral data is as follows: 1H NMR IR triplet, δ 1.0 singlet, δ2.4 2200 cm-1 (sharp) singlet, δ 1.4 singlet, δ3.4 3300 cm-1 (sharp) quartet, δ 1.6 3500 cm-1 (broad)

II

OH

III

IV VOH

I

OH OH

OH

A) I B) II C) III D) IV E) V

Ans: C

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Topic: C-13 NMR- Symmetry, Chemical shift.

37. The broadband proton-decoupled 13C NMR spectrum of a hexyl chloride exhibits five signals. Which of these structures could be the correct one for the compound?

A)

CH3CCH2CH2Cl

CH3

CH3

B)

CH3CH2CCH2CH3

Cl

CH3

C)

CH3C CHCH3

CH3

Cl

CH3

D)

CH3CHCHCH2CH3

CH3

Cl

E)

CH3C CHCH3

CH3

CH3 Cl

Ans: D Topic: C-13 NMR- Symmetry, Chemical shift

38. How many signals will be recorded in the broadband proton-decoupled 13C spectrum of 4-chloro-1-ethylbenzene? Cl

A) 2 B) 3 C) 4 D) 6 E) 7

Ans: D

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Topic: C-13 NMR- Symmetry, Chemical shift

39. How will the methyl carbon appear in the proton off-resonance decoupled 13C spectrum of toluene?

A) Singlet B) Doublet C) Triplet D) Quartet E) Quintet

Ans: D Topic: C-13 NMR- Symmetry, Chemical shift

40. How many 13C signals would 1,4-dimethylbenzene give?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C Topic: C-13 NMR- Symmetry, Chemical shift

41. How many 13C signals would 1,3-dichlorobenzene give?

Cl

Cl

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: D

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Topic: C-13 NMR- Symmetry, Chemical shift

42. How many 13C signals would 1,2-dimethylbenzene give?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: D Topic: C-13 NMR- Symmetry, Chemical shift

43. How many 13C signals would you expect from C6H5OCH3? O

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: E Topic: C-13 NMR- Symmetry, Chemical shift

44. The C7 compound which gives 3 signals in the broadband proton-decoupled 13C spectrum could be:

A) Heptane B) 2-Methylhexane C) 3,3-Dimethylpentane D) 2,4-Dimethylpentane E) 2,2,3-Trimethylbutane

Ans: D

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Topic: Proton NMR- Symmetry, Splitting, Chemical shift

45. Which of these compounds will not be represented by a singlet only in the 1H NMR spectrum?

A) Neopentane B) Hexamethylbenzene C) Isobutane D) (Z)-1,2-Dichloroethene E) (E)-1,2-Dichloroethene

Ans: C Topic: Proton NMR- Symmetry, Splitting, Chemical shift

46. For the C2 methylene group in 1-bromopropane, the theoretical multiplicity in the 1H NMR spectrum, presuming that Jab is sufficiently different from Jbc and that the instrument has sufficient resolving power, is which of these?

CH3 CH2 CH2 Br

c b aA) 2 B) 5 C) 6 D) 8 E) 12

Ans: E Topic: Proton NMR- Symmetry, Splitting, Chemical shift 47. A compound C5H11Cl which exhibits only two singlets in the 1H NMR spectrum must

be: A) 1-Chloropentane B) 1-Chloro-2,2-dimethylpropane C) 1-Chloro-2-methylbutane D) 3-Chloropentane E) 1-Chloro-3-methylbutane

Ans: B

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Topic: Proton NMR- Symmetry, Splitting, Chemical shift

48. A downfield (δ 9-10) singlet is observed in the 1H NMR spectrum of: A)

CH3CCH2CH3

O

B)

C6H5CH2C O

H

C)

(CH3)2CHC O

H

D)

(CH3)3CC O

H

E)

C6H5CH2CCH3

O

Ans: D Topic: Proton NMR- Symmetry, Splitting, Chemical shift 49.

Consider the expected splitting of signal “b” in the 1H NMR spectrum of N-methyl-1-propanamine, shown below. Presuming that Jab is sufficiently different from Jbc and that the instrument has sufficient resolving power, what is the theoretical multiplicity of signal “b”?

HN

a

b

c

d

e

A) 2 B) 5 C) 6 D) 8 E) 12

Ans: E

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50. Consider the expected splitting of signal “b” in the 1H NMR spectrum of 1-methoxy-2-methylpropane, shown below. Presuming that Jab is sufficiently different from Jbc and that the instrument has sufficient resolving power, what is the theoretical multiplicity of signal “b”?

O

a b c d

a

A) 8 B) 9 C) 12 D) 21 E) 24

Ans: D Topic: Proton NMR- Symmetry, Splitting, Chemical shift

51. Consider the expected splitting of signal “b” in the 1H NMR spectrum of 1,1-dichloro-3-methylbutane, shown below. Presuming that Jab is sufficiently different from Jbc and that the instrument has sufficient resolving power, what is the theoretical multiplicity of signal “b”?

Cla b c

a Cl

d

A) 8 B) 9 C) 12 D) 18 E) 21

Ans: E

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Topic: Proton NMR- Symmetry, Splitting, Chemical shift

52. Consider the expected splitting of signal “b” in the 1H NMR spectrum of 1,2-dimethoxypropane, shown below. Presuming that Jbc is sufficiently different from Jbd and that the instrument has sufficient resolving power, what is the theoretical multiplicity of signal “b”?

O

Oa b

d

c

e

A) 2 B) 5 C) 6 D) 8 E) 12

Ans: E Topic: Proton NMR- Symmetry, Splitting, Chemical shift

53.

Consider the expected splitting of signal “c” in the 1H NMR spectrum of 2-ethyl-1-butanol, shown below. Presuming that Jbc is sufficiently different from Jcd and that the instrument has sufficient resolving power, what is the theoretical multiplicity of signal “c”?

OHa

b dc e

ab

A) 6 B) 7 C) 8 D) 12 E) 15

Ans: E

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54.

Consider the expected splitting of the C2 proton signal in the 1H NMR spectrum of 2-ethyl-1,3-propanediol. Presuming that the coupling constants for neighboring protons are sufficiently different, and that the instrument has sufficient resolving power, what is the theoretical multiplicity of the C2 proton signal?

A) 6 B) 7 C) 8 D) 12 E) 15

Ans: E Topic: Proton NMR- Symmetry, Splitting, Chemical shift

55.

What is the theoretical multiplicity of the C-2 proton signal in the 1H NMR spectrum of 2-hydroxymethyl-1,3-propanediol, shown below?

OHHO

OH

A) 1 B) 6 C) 7 D) 8 E) 9

Ans: C Topic: Proton NMR- Symmetry, Splitting, Chemical shift

56.

Consider the expected 1H NMR spectrum of 1,1,3,3-trimethylcyclopentane. Which of the following is likely to be observed?

A) 7 signals: all singlets B) 7 signals: 4 singlets, 3 doublets C) 3 signals: all singlets D) 3 signals: one singlet, 2 doublets E) 3 signals: two singlets, one doublet

Ans: E

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Topic: Proton NMR- Symmetry, Splitting, Chemical shift

57.

Consider the expected 1H NMR spectrum of 2,4-dimethyl-1,4-pentadiene. Which of the following is likely to be observed?

A) 7 signals: all singlets B) 4 signals: all singlets C) 3 signals: all singlets D) 3 signals: one singlet, 2 doublets E) 4 signals: two singlets, two doublets

Ans: B Topic: Proton NMR- Symmetry, Splitting, Chemical shift

58.

Consider the expected splitting of the C2 proton signal in the 1H NMR spectrum of 1,1-dibromopentane. Presuming that the coupling constants for neighboring protons are sufficiently different, and that the instrument has sufficient resolving power, what is the theoretical multiplicity of the C2 proton signal?

A) 3 B) 4 C) 5 D) 6 E) 8

Ans: D

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Topic: Carbon NMR- Symmetry, Chemical shift

59. A bromodichlorobenzene which gives four signals in the broadband proton-decoupled 13C spectrum could be:

Br

I

Br

II

Cl

III

Cl

IV V

Cl

Cl

Cl

Cl

Br

Cl

Br

Cl

Br

Cl

Cl

A) I B) II C) III D) IV E) V

Ans: A Topic: Carbon NMR- Symmetry, Chemical shift

60. In 13C NMR spectroscopy, the signal due to this type of carbon occurs furthest downfield.

A) –C≡N B)

C O

C) C O

D) C X

E) –C≡C– Ans: B

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Topic: Mass Spectrometry. Use the following to answer Q 61-62

Topic: Mass Spectrometry.

61. Which is the base peak? A) 15 B) 29 C) 44 D) 45 E) 100

Ans: B Topic: Mass Spectrometry.

62. Which is the likely molecular ion (M+•)?

A) 15 B) 29 C) 44 D) 45 E) 100

Ans: C Topic: Mass Spectrometry.

63. What is the molecular formula of this compound? m/z intensity 84 M+

• 10.00 85 0.56 86 0.04

A) C5H10O B) C5H8O C) C5H24 D) C6H12 E) C4H6O2

Ans: B

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Topic: Mass Spectrometry.

64. What is the molecular formula of this compound? m/z intensity 78 M+

• 10.00 79 1 80 3.3 81 0.3

A) C6H6 B) C3H5Cl C) C6H8 D) C6H9 E) C3H7Cl

Ans: E Topic: Mass Spectrometry.

65. The mass spectra of alkyl bromides and chlorides are characterized by an unusually intense __________.

A) base peak B) parent peak C) M+

• +1 peak D) M+

• +2 peak E) None of these

Ans: D Topic: Mass Spectrometry. 66. Predict the base peak for 2-chloro-2-methylpropane

A) m/z 15 B) m/z 92 C) m/z 43 D) m/z 57 E) m/z 77

Ans: D

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Topic: Mass Spectrometry.

67. Select the structure of a compound C6H14 with a base peak at m/z 43. A) CH3CH2CH2CH2CH2CH3 B) (CH3CH2)2CHCH3 C) (CH3)3CCH2CH3 D) (CH3)2CHCH(CH3)2 E) None of these

Ans: D Topic: Mass Spectrometry.

68. The data below from the molecular ion region of the mass spectrum of a halogen-containing compound are consistent with the presence of what halogen(s) in the original compound? intensity M+

• 51.0 M+

• +2 100.0 M+

• +4 49.0

A) One Br B) One Cl C) One Br and one Cl D) Two Br E) Two Cl

Ans: D Topic: Mass Spectrometry.

69. A prominent (M+• -18) peak suggests that the compound might be a(n):

A) alkane B) alcohol C) ether D) ketone E) primary amine

Ans: B

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Topic: Structure Elucidation

70. An organic compound absorbs strongly in the IR at 1687 cm-1. Its 1H NMR spectrum consists of two signals, a singlet at 2.1 ppm and a multiplet centered at 7.1 ppm. Its mass spectrum shows significant peaks at m/z 120, m/z 105 and m/z 77. This information is consistent with which of the following structures?

O

I

O

II

O

III

IV VA) I B) II C) III D) IV E) V

Ans: A SHORT ANSWER QUESTIONS Topic: General

71. Which form of electromagnetic radiation possesses the least energy? Ans: radiofrequency radiation

Topic: General

72. “NMR” stands for _______________________. Ans: nuclear magnetic resonance

Topic: General; Signal Integration

73. When measuring the integral for a particular peak in the NMR spectrum, we are not interested in the peak height as much as in the ____________________. Ans: area under the peak

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Topic: General; Chemical Shift

74. A shielded proton will absorb at a higher frequency (this is the ________ end of the spectrum); and a deshielded proton will absorb at a lower frequency (the _____________ end of the spectrum). Ans: upfield; downfield

Topic: Reference Compound

75. What compound is used as the standard “zero” reference in both carbon and proton NMR? Ans: TMS or tetramethylsilane or (CH3)4 Si

Topic: General, Bond Rotation, Proton Exchange

76. Name two rapid processes that occur in organic molecules. Ans: Rotation about C-C single bonds; chemical exchange of protons attached to

electronegative atoms Topic: Molecular Ion

77. In electron impact mass spectrometry, a beam of high-energy electrons initially dislodges one electron from the compound being studied. This produces a positively charged ion called the ____________________. Ans: molecular ion

Topic: Nitrogen Rule

78. What is the nitrogen rule? Ans: If the molecular ion peak is even, the molecule must contain an even number of

nitrogen atoms (zero is an even number). If the molecular ion peak is odd, the molecule must contain an odd number of nitrogen atoms.)

Topic: Relative Abundance

79. What can be determined from the relative abundance of the M+• +1 peak?

Ans: An approximation for the number of carbon atoms in the molecule. Topic: Relative Abundance

80. What can be determined from the relative abundance of the M+• +2 peak?

Ans: The presence of a number of different elements, including S, Br, and Cl.

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Topic: Base Peak

81. In mass spectrometry, the most intense peak is assigned an intensity of 100%, and is referred to as the ______________. Ans: base peak

Topic: m/z Ratio

82. A mass spectrometer sorts ions on the basis of their _______________. Ans: mass to charge ratio

Topic: Structure Elucidation

83. Briefly explain how you might distinguish between the following substances by comparing their 1H-NMR spectra:

O

O

I

O

O

IIAns: The main difference would likely be in the chemical shift of the methine proton of

the isopropyl group. The methine proton in I is likely to be more deshielded, and produce a signal (septet) at about 3.5 ppm, while the analogous proton in II is likely to be found, also as a septet, at about 2.3 ppm.

I II

O

OO

O

~3.5 ppm ~2.3 ppm

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Topic: Structure Elucidation

84. Briefly explain how you might distinguish between the following substances by comparing their 1H-NMR spectra:

O

O

I

O

OII

Ans: The main difference would likely be in the chemical shifts of the methine proton of the isopropyl group and the methylene proton closest to the ester function. The methine proton in I is likely to be more deshielded, and produce a signal (septet) at about 3.5 ppm, while the analogous proton in II is likely to be found, also as a septet, at about 2.3 ppm. By contrast, the methylene proton in II is likely to be more deshielded, and produce a signal (triplet) at about 3.4 ppm, while the analogous proton in II is likely to be found, also as a triplet, at about 2.2 ppm.

O

OO

O

I II

~3.5 ppm(septet)

~2.3 ppm(septet)

~2.2 ppm(triplet)

~3.4 ppm(triplet)

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Topic: Structure Elucidation

85. Briefly explain how you might distinguish between the following substances by comparing their 1H-NMR spectra:

NH

O

I

HN

OII

Ans: The main difference would likely be in the chemical shifts of the methine proton of the isopropyl group and the methylene proton closest to the amide function. The methine proton in I is likely to be more deshielded, and produce a signal (septet) at about 3.5 ppm, while the analogous proton in II is likely to be found, also as a septet, at about 2.3 ppm. By contrast, the methylene proton in II is likely to be more deshielded, and produce a signal (triplet) at about 3.4 ppm, while the analogous proton in II is likely to be found, also as a triplet, at about 2.2 ppm.

NH

O HN

O

I II

~3.2 ppm(septet)

~2.3 ppm(septet)

~2.2 ppm(triplet)

~3.1 ppm(triplet)

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Topic: Structure Elucidation 86.

An unknown compound, A, has the formula C7H14O. Elucidate the structure of A by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

Ans: O

4-Heptanone

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Topic: Structure Elucidation 87.

An unknown compound, C, has the formula C7H7Br. Elucidate the structure of C by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

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Ans:

Br 4-Bromotoluene

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Topic: Structure Elucidation

88. An unknown compound, E, has the formula C6H12O. Elucidate the structure of E by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

Ans: O

2-Hexanone

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Topic: Structure Elucidation

89. An unknown compound, F, has the formula C3H6O2. Elucidate the structure of F by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

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318

Ans:

OH

O

Propanoic acid

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Topic: Structure Elucidation

90. An unknown compound, I, has the formula C3H7NO2. Elucidate the structure of I by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

Ans: NO2 1-Nitropropane

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Topic: Structure Elucidation

91. An unknown compound, L, has the formula C5H10O2. Elucidate the structure of L by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

Ans:

O

O

Methyl butyrate

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Topic: Structure Elucidation

92. An unknown compound, U, has the formula C6H4Cl2O. Elucidate the structure of U by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

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Ans: OH

Cl Cl

2,6-dichlorophenol

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Topic: Structure Elucidation

93. An unknown compound, V, has the formula C8H10O. Elucidate the structure of V by scrutinizing its IR, 1H NMR and 13C NMR spectra, shown below.

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Ans: OH

2,6-dimethylphenol

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Topic: Structure Elucidation

94. Examine the 1H NMR spectrum of 1-nitropropane, shown below. Assign the signals to the respective hydrogen atoms in the molecule.

Ans:

>>

>

NO21.0 ppmtriplet

2.0 ppmsextet

4.3 ppmtriplet

Topic: 1H NMR

95. Predict the 1H NMR spectrum of 2-chloroethanal, CH2ClCHO.

Ans:

ClO>

4-5 ppmdoublet

>

9-10 ppmtriplet

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Topic: 1H NMR

96. Predict the number of signals in the 1H NMR spectrum of 2-methyl-2-pentanol. Ans: Five

OH

1 2 4

3

5

1'

Topic: 13C NMR, Structure Elucidation

97. Interpret the following 13C/DEPT spectrum of a compound C5H10Br2: elucidate the structure and assign all the 13C resonances.

Ans:

Br Br

>

32 ppm

>

>

27 ppm

>

33 ppm

>

33 ppm

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Topic: 1H NMR

98. Predict the 1H NMR spectrum of diethoxymethane, CH3CH2OCH2OCH2CH3.

Ans:

O O

>~4.9 ppmsinglet

>

~3.4 ppmquartet

>

~3.4 ppmquartet

>

~1.2 ppmtriplet

>

~1.2 ppmtriplet

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MULTIPLE CHOICE QUESTIONS Topic: Delta H Calculations and Comparisons

1. The bond dissociation energies for the relevant bonds are given below each of the species involved in the following reaction. Calculate the overall ΔH° for the reaction. (CH3)3C-H + Cl-Cl (CH3)3C-Cl + H-Cl

ΔHo=400 kJ/mol ΔHo=243 kJ/mol ΔHo=349 kJ/mol ΔHo=432 kJ/mol

A) +243 kJ / mol B) -138 kJ / mol C) +138 kJ / mol D) -781 kJ / mol E) +781 kJ / mol

Ans: B Topic: Delta H Calculations and Comparisons

2. The bond dissociation energies for the relevant bonds are given below each of the species involved in the following reaction. Calculate the overall ΔH° for the reaction. CH3CH2CH2-H + Br-Br CH3CH2CH2-Br + H-Br

ΔHo=423 kJ/mol ΔHo=193 kJ/mol ΔHo=294 kJ/mol ΔHo=366 kJ/mol

A) +616 kJ / mol B) -101 kJ / mol C) -173 kJ / mol D) +57 kJ kJ / mol E) -44 kJ / mol

Ans: E

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Topic: Delta H Calculations and Comparisons

3. The bond dissociation energies for the relevant bonds are given below each of the species involved in the following reaction. Calculate the overall ΔH° for the reaction. CH3CH2-H + Cl-Cl CH3CH2-Cl + H-Cl

ΔHo=353 kJ/mol ΔHo=432 kJ/molΔHo=421 kJ/mol ΔHo=243 kJ/mol

A) -121 kJ / mol B) +121 kJ / mol C) +243 kJ / mol D) +664 kJ / mol E) -785 kJ / mol

Ans: A Topic: Delta H Calculations and Comparisons

4. The bond dissociation energies for the relevant bonds are given below each of the species involved in the following reaction. Calculate the overall ΔH° for the reaction. (CH3)2CH-H + F-F (CH3)2CH-F + H-F

ΔHo=413 kJ/mol ΔHo=159 kJ/mol ΔHo=439 kJ/mol ΔHo=570 kJ/mol

A) +437 kJ / mol B) -437 kJ / mol C) -411 kJ / mol D) +26 kJ / mol E) -1581 kJ / mol

Ans: B Topic: Delta H Calculations and Comparisons

5. Which of the reactions listed below would have a value of ΔH° equal to zero? A) H–H ⎯⎯⎯⎯→ 2H· B) H· + CH3–H ⎯⎯⎯⎯→ CH3–H + H· C) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3 D) CH3· + CH3–H ⎯⎯⎯⎯→ CH3–H + CH3· E) Reactions (B) and (D)

Ans: E

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Topic: Delta H Calculations and Comparisons

6. Which of the reactions listed below would be exothermic? A) CH3–CH3 ⎯⎯⎯⎯→ 2CH3· B) CH3· + CH4 ⎯⎯⎯⎯→ CH4 + CH3· C) 2(CH3)2CH· ⎯⎯⎯⎯→ (CH3)2CH–CH(CH3)2 D) H· + (CH3)3CH ⎯⎯⎯⎯→ (CH3)3CH + H· E) None of the above

Ans: C Topic: Delta H Calculations and Comparisons

7. Which of the reactions listed below would be exothermic? A) H–H ⎯⎯⎯⎯→ 2H· B) H· + CH3–H ⎯⎯⎯⎯→ CH3–H + H· C) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3 D) CH3· + CH3–H ⎯⎯⎯⎯→ CH3–H + CH3· E) All of the above

Ans: C Topic: Activation Energies

8. Which reaction would you expect to have the smallest energy of activation? ΔH°(kJ mol-1)

A) CH3· + CH3· ⎯⎯⎯⎯→ CH3CH3 -378 B) CH4 + F· ⎯⎯⎯⎯→ CH3· + HF -130 C) CH4 + I· ⎯⎯⎯⎯→ CH3· + HI +142 D) CH4 + Br· ⎯⎯⎯⎯→ CH3· + HBr +104 E) CH4 + Cl· ⎯⎯⎯⎯→ CH3· + HCl +8

Ans: A Topic: Activation Energies

9. Which of the following reactions would have an activation energy equal to zero? A) CH3–CH3 ⎯⎯⎯⎯→ 2CH3· B) H· + CH3CH3 ⎯⎯⎯⎯→ CH3CH3 + H· C) 2CH3CH2· ⎯⎯⎯⎯→ CH3CH2CH2CH3 D) CH3· + CH3CH3 ⎯⎯⎯⎯→ CH3CH3 + CH3· E) None of the above

Ans: C

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Topic: Activation Energies

10. Which of the following reactions would have the smallest energy of activation? A) CH4 + Br· ⎯⎯⎯⎯→ CH3· + HBr B) CH3CH3 + Br· ⎯⎯⎯⎯→ CH3CH2· + HBr C) CH3CHCH3

+CH3CHCH2

+ HBrBrCH3 CH3

D) CH3CHCH3

+CH3CCH3

+ HBrBrCH3 CH3

E)

C CH2CH3

CH3

CH3

+ HBrC CH3CH3

CH3

CH3

+ Br

Ans: D Topic: Activation Energies

11. Which of the following reactions would have the smallest energy of activation? A) + Br + HBr.

.

B) + Br + HBr.

.C) + Br + HBr..

D) + Br + HBr..

E) + Br + HBr..

Ans: C Topic: Activation Energies

12. An example of a reaction having an Eact = 0 would be: A) Br· + Br–Br ⎯⎯⎯⎯→ Br–Br + Br· B) F· + CH4 ⎯⎯⎯⎯→ H–F + CH3· C) CH3· + CH3CH3 ⎯⎯⎯⎯→ CH4 + CH3CH2· D) Br· + H–Br ⎯⎯⎯⎯→ H–Br + Br· E) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3

Ans: E

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Topic: Activation Energies

13. Which of the following reactions should have the smallest energy of activation? A) CH4 + Cl· ⎯⎯⎯⎯→ CH3· + HCl B) CH3CH3 + Cl· ⎯⎯⎯⎯→ CH3CH2· + HCl C) CH3CHCH3

+CH3CHCH2

+ HClClCH3 CH3

D) CH3CHCH3

+CH3CCH3

+ HClClCH3 CH3

E)

C CH2CH3

CH3

CH3

+ HClC CH3CH3

CH3

CH3

+ Cl

Ans: D Topic: Activation Energies

14. Which reaction would you expect to have the largest energy of activation? ΔH° (kJ mol-1)

A) CH3· + CH3· ⎯⎯⎯⎯→ CH3CH3 -378 B) CH3· + Br· ⎯⎯⎯⎯→ CH3Br -130 C) CH4 + I· ⎯⎯⎯⎯→ CH3· + HI +142 D) CH4 + Br· ⎯⎯⎯⎯→ CH3· + HBr +104 E) CH4 + Cl· ⎯⎯⎯⎯→ CH3· + HCl +8

Ans: C Topic: Activation Energies

15. An example of a reaction having an Eact = 0 would be: A) Br· + Br–Br ⎯⎯⎯⎯→ Br–Br + Br· B) F· + CH4 ⎯⎯⎯⎯→ H–F + CH3· C) CH3· + Cl· ⎯⎯⎯⎯→ CH3Cl D) More than one of these E) None of these

Ans: C

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Topic: Activation Energies

16. Which of the following reactions would have an activation energy equal to zero? A) H–H ⎯⎯⎯⎯→ 2H· B) H· + CH3–H ⎯⎯⎯⎯→ CH3––H + H· C) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3 D) CH3· + CH3–H ⎯⎯⎯⎯→ CH3–H + CH3· E) All of the above

Ans: C Topic: Activation Energies 1. Given the following bond dissociation energies:

ΔH° (kJ mol-1) CH3CH2–H 421 H–F 570 H–Cl 432 H–Br 366 H–I 298 predict which of the following reactions would have the highest energy of activation.

A) CH3CH3 + F· ⎯⎯⎯⎯→ CH3CH2· + HF B) CH3CH3 + Cl· ⎯⎯⎯⎯→ CH3CH2· + HCl C) CH3CH3 + Br· ⎯⎯⎯⎯→ CH3CH2· + HBr D) CH3CH3 + I· ⎯⎯⎯⎯→ CH3CH2· + HI E) ΔH° values are important, but not sufficient for this prediction Ans: D

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Topic: Activation Energies 18. Given the following bond dissociation energies:

ΔH°(kJ mol-1) CH3–H 440 H–F 570 H–Cl 432 H–Br 366 H–I 298 predict which of the following reactions would have the highest energy of activation.

A) CH4 + F· ⎯⎯⎯⎯→ CH3· + HF B) CH4 + Cl· ⎯⎯⎯⎯→ CH3· + HCl C) CH4 + Br· ⎯⎯⎯⎯→ CH3· + HBr D) CH4 + I· ⎯⎯⎯⎯→ CH3· + HI E) ΔH° values are important, but not sufficient for this prediction

Ans: D Topic: Activation Energies

19. For which of the following gas-phase reactions would the Eact be equal to ΔH°? A) Cl–Cl ⎯⎯⎯⎯→ 2Cl· B) 2 Cl· ⎯⎯⎯⎯→ Cl–Cl C) Cl· + CH4 ⎯⎯⎯⎯→ CH3· + H–Cl D) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3 E) CH3· + Cl–Cl ⎯⎯⎯⎯→ CH3–Cl + Cl·

Ans: A Topic: Reaction Products (Isomers)

20. In the presence of light, ethane (1 mol) reacts with chlorine (1 mol) to form which product(s)?

A) CH2ClCHCl2 B) CH3CHCl2 C) CH3CH2Cl D) ClCH2CH2Cl E) All of these

Ans: E

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Topic: Reaction Products (Isomers)

21. How many different monochlorobutanes (including stereoisomers) are formed in the free radical chlorination of butane?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C Topic: Reaction Products (Isomers)

22. The reaction of 2-methylbutane with chlorine would yield how many monochloro derivatives? (include stereoisomers)

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: E Topic: Reaction Products (Isomers) 23. The reaction of 2,2-dimethylbutane with chlorine would yield how many monochloro

derivatives? (include stereoisomers) A) 1 B) 2 C) 3 D) 4 E) 5

Ans: D Topic: Reaction Products (Isomers)

24. The free radical chlorination of pentane produces this number of monochloro compounds, including stereoisomers.

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: C

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25. Free radical chlorination will produce but one monochloro derivative in the case of: A) Propane. B) Butane. C) Isobutane. D) Isopentane. E) Neopentane.

Ans: E Topic: Reaction Products (Isomers)

26. Free radical chlorination of hexane produces this number of monochloro derivatives (including stereoisomers):

A) 3 B) 4 C) 5 D) 7 E) 8

Ans: C Topic: Reaction Products (Isomers)

27. More than one monochloro compound can be obtained from the free radical chlorination of:

A) Cyclopentane B) Neopentane C) Isobutane D) Ethane E) Methane

Ans: C Topic: Reaction Products (Isomers)

28. What is the total number of trichloropropanes which can be produced by free radical chlorination of propane? Include all stereoisomers.

A) 4 B) 5 C) 6 D) 7 E) 8

Ans: C

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29. If chlorocyclopentane were chlorinated to form all possible dichloro compounds and the product mixture subjected to precise fractional distillation, how many fractions would be obtained (ideally)?

A) 3 B) 4 C) 5 D) 7 E) 9

Ans: C Topic: Reaction Products (Isomers)

30. The free radical chlorination of (R)-2-chloropentane forms a mixture of dichloropentanes which includes:

A) three optically active compounds B) two achiral compounds. C) two meso compounds. D) one pair of diastereomers. E) one racemic mixture.

Ans: B Topic: Reaction Products (Isomers)

31. How many monochloro derivatives, including stereoisomers, can be formed in the chlorination of 1-bromobutane?

A) 4 B) 5 C) 6 D) 7 E) 8

Ans: D Topic: Reaction Products (Isomers)

32. The free radical chlorination of 3-chloropentane forms a mixture of dichloropentanes which, on precise fractional distillation, affords these fractions:

A) 4 fractions, none optically active B) 4 fractions, 2 optically active C) 7 fractions, 4 optically active D) 7 fractions, 6 optically active E) 7 fractions, all optically active

Ans: A

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33. Consider the light-initiated chlorination of (S)-2-chlorobutane followed by careful fractional distillation (or separation by GLC) of all of the products with the formula C4H8Cl2. How many fractions (in total) would be obtained and how many of these fractions would be optically active?

A) Three fractions total; all optically active B) Four fractions total; three fractions optically active C) Five fractions total; all optically active D) Five fractions total; four fractions optically active E) Five fractions total; three fractions optically active

Ans: E Topic: Reaction Products

34. What is the product of the reaction

CH3CH2CH CH2 + CBr4peroxides

?A) CH3CH2CH=CHCBr3 B) CH3CH2CHCH2CBr3

Br

C) CH3CH2CHCH2Br

CBr3

D) CH3CH2CH2CH2CBr3 E) No reaction occurs.

Ans: B

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35. Select the structure of the major product formed in the following reaction.

I II III IV V

CH3

CH2Br CH3 Br CH3CH3BrBr

Br

Br2

hν?

A) I B) II C) III D) IV E) V

Ans: B Topic: Reaction Products 36. What would be the major product of the following reaction?

I II III IV V

CH3

CH3

Br

CH3Br

CH3

OR

CH3

BrCH3

Br

?HBr

peroxides

A) I B) II C) III D) IV E) V

Ans: A

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37. In the presence of light at 25°C, isobutane (1 mol) and bromine (1 mol) yield which monobromo product(s)?

A) 2-Methyl-1-bromopropane (almost exclusively) B) 2-Methyl-2-bromopropane (almost exclusively) C) A mixture of 50% (A) and 50% (B) D) A mixture of 90% (A) and 10% (B) E) Butyl bromide

Ans: B Topic: Reaction Products

38. Which of these molecules is not expected to arise as a product of the high temperature chlorination of methane?

A) CCl4 B) HCCl3 C) CH2Cl2 D) CH3CH3 E) CH2=CH2

Ans: E Topic: Reaction Products 39. In a competition reaction, equimolar amounts of five alkanes compete for a deficiency

of chlorine at 300°C. The greatest amount of reaction would occur in the case of which of these alkanes?

A) Ethane B) Propane C) Butane D) Isobutane E) Pentane

Ans: D Topic: Reaction Products

40. Which of the following combinations of reactants can provide a demonstrable example of anti-Markovnikov addition?

A) CH2=CHCH3 + HCl + ROOR B) CH3CH=CH2 + H2O + Cl2 C) CH3CH=CHCH3 + HBr + ROOR D) CH3CH2CH=CH2 + HBr + ROOR E) CH3CH2CH=CH2 + Br2 + ROOR

Ans: D

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41. 2-Methyl-2-butene reacts with HBr in the presence of peroxide to give (chiefly): A) (CH3)2CHCH2CH2Br B) (CH3)2CHCHCH3

Br

C) (CH3)2CCH2CH3

Br

D)

BrCH2CHCH2CH3

CH3

E)

(CH3)2CCHCH3

Br

BrAns: B

Topic: Reaction Products

42. What product would result from the following reaction?

I II III IV V

Br Br HOO Br Br OOH

Br

+ HBrperoxides ?

A) I B) II C) III D) IV E) V

Ans: A

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43. Which of the following would serve as the best synthesis of 2-bromohexane? A)

+ HBrperoxides

CH2 CHCH2CH2CH2CH3 heatB)

+ HBrheat

CH2 CHCH2CH2CH2CH3

C) + HBrCH3CH2 CHCH2CH2CH3

heat

D) peroxides

heat+ HBrCH3CH2 CHCH2CH2CH3

E) All of the above would be equally suitable. Ans: B

Topic: Synthesis

44. Which would be the best way to carry out the following synthesis? ?

(CH3)3COH (CH3)2CHCH2Br

A) (1) HA, heat; (2) HBr B) (1) HBr and peroxides; (2) Br2/CCl4 C) (1) HA, heat; (2) HBr and peroxides D) (1) Br2/CCl4; (2) HA, heat E) (1) HA, heat; (2) Br2/CCl4

Ans: C Topic: Reaction Products

45. What sequence of reactions could be used to prepare cis-1,2-cyclopentanediol from cyclopentane?

A) (1) Cl2, hν; (2) t-BuOK/t-BuOH; (3) OsO4; (4) NaHSO3/H2O B) (1) t-BuOK/t-BuOH; (2) Cl2, hν; (3) NaOH/H2O C) (1) Cl2, hν; (2) t-BuOK/t-BuOH; (3) H2O2 D) (1) NaOH/H2O; (2) Br2; (3) NaNH2(2eq.)/liq.NH3; (4) KMnO4, NaOH/H2O, 5°C E) (1) Cl2, hν; (2) t-BuOK/t-BuOH; (3) Hg(OAc)2, H2O (4) NaBH4, H3O+

Ans: A

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46. Carbocations are NOT intermediates in which one of the following reactions? A)

+ HBrBr

B) + H2SO4

OH

C) + BH3

HH2B

D) OSO3H+ H2SO4

E) Br+ HBr

R-O-O-R

Ans: E Topic: Mechanisms

47. A chain reaction is one that: A) involves a series of steps. B) involves two steps of equal activation energy. C) is one that can be initiated by light. D) involves a series of steps, each of which generates a reactive intermediate that brings

about the next step. E) involves free radicals that have an unusual stability and thereby cause a large quantum

yield. Ans: D

Topic: Mechanisms

48. Which of the following statements is true when used to compare the reaction of fluorine with 2-methylhexane and the reaction of bromine with 2-methylhexane?

A) Bromine is the less reactive and the less selective, giving 2-bromo-2-methyl hexane as one of several products.

B) Fluorine is the less reactive and the more selective, giving 2-fluoro-2-methyl hexane as the major product.

C) Fluorine is the more reactive and less selective, giving 2-fluoro-2-methyl hexane as one of several products.

D) Bromine is the more reactive and the more selective, giving 2-bromo-2-methyl hexane as the major product.

E) More than one of the above statements is true Ans: C

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49. An alternate mechanism for the chlorination of methane is: Cl2 ⎯⎯⎯⎯→ 2Cl· Cl–Cl, ΔH° = 243 kJ mol-1

Cl· + CH4 ⎯⎯⎯⎯→ CH3Cl + H· CH3–H, ΔH° = 440 kJ mol-1

H· + Cl2 ⎯⎯⎯⎯→ HCl + Cl· CH3–Cl, ΔH° = 352 kJ mol-1

H–Cl, ΔH° = 432 kJ mol -1

This mechanism is unlikely because:

A) The overall ΔH° is highly endothermic. B) The probability factor is low. C) One of the chain propagating steps is non-productive. D) One of the chain propagating steps has a very high Eact. E) One of the chain propagating steps is highly exothermic.

Ans: D Topic: Mechanisms

50. Which statement(s) is(are) true about the reaction of bromine with isobutane? A) Bromine selectively abstracts the tertiary hydrogen. B) The transition state of the rate determining step is product-like. C) The major product formed from this reaction is 1-bromo-2-methylpropane. D) A) and B) E) A), B) and C)

Ans: D Topic: Mechanisms

51. For which reaction would the transition state be most product-like? A) CH4 + Br· ⎯⎯⎯⎯→ CH3· + HBr B) CH3CH3 + Br· ⎯⎯⎯⎯→ CH3CH2· + HBr C)

+CH3CHCH2

+ HBrBrCH3

CH3CHCH3

CH3

D)

+CH3CCH3

+ HBrBrCH3

CH3CHCH3

CH3

E)

+ CH3CCH2 + HBrBr

CH3

CH3CCH3

CH3

CH3 CH3

Ans: A

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52. For which of the following reactions would the transition state most resemble the products? The following bond dissociation energies may be useful. (CH3)2CH–H CH3CH2CH2–H H–F (413 kJ mol-1) (423 kJ mol-1) (570 kJ mol-1) H–Cl H–Br (432 kJ mol-1) (366 kJ mol-1)

A)

B) CH3CH2CH3 + F· ⎯⎯⎯⎯→ CH3CH2CH2· + HF C)

D) CH3CH2CH3 + Cl· ⎯⎯⎯⎯→ CH3CH2CH2· + HCl E) CH3CH2CH3 + Br· ⎯⎯⎯⎯→ CH3CH2CH2· + HBr

Ans: E Topic: Mechanisms

53. Which of the following gas-phase reactions is a possible chain-terminating step in the light-initiated chlorination of methane?

A) Cl–Cl ⎯⎯⎯⎯→ 2Cl· B) Cl· + CH4 ⎯⎯⎯⎯→ CH3· + H–Cl C) CH3· + CH3· ⎯⎯⎯⎯→ CH3–CH3 D) CH3· + Cl–Cl ⎯⎯⎯⎯→ CH3Cl + Cl· E) More than one of the above

Ans: C Topic: Mechanisms

54. The reaction of 1-butene with HBr in the presence of peroxides yields 1-bromobutane. The mechanism for the reaction involves:

A) attack on the alkene by a Br+ ion. B) attack on the alkene by a H+ ion. C) attack on the alkene by a bromine atom, Br·. D) attack on the alkene by a hydrogen atom, H·. E) isomerization of the 2-bromobutane produced initially.

Ans: C

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55. The reaction of Cl2 with a methyl radical has a positive ΔH°. Which of these drawings is the best representation of the transition state of this reaction?

A)

C

H

ClClδ - δ -

HH

B) C

H

H

HClCl

C) C

H

H

HClClδ - δ -

D) C

H

H

HClCl +

E) C

H

H

Hδ - δ -

ClCl

Ans: E Topic: Free Radicals 56. The hybridization state of the carbon of a methyl radical is: A) sp B) sp2 C) sp3 D) sp4 E) p3 Ans: B Topic: Free Radicals

57. The p-orbital of a methyl radical carbon, CH3·, contains how many electrons? A) 1 B) 2 C) 3 D) 4 E) 0

Ans: A

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58. Which of the following free radicals is the most stable? A)

CH3CHCH2CH3

CH2

B)

CH3CHCH2CH2

CH3

C)

CH2CHCH2CH3

CH3

D)

CH3CHCHCH3

CH3

E)

CH3CCH2CH3

CH3

Ans: E Topic: Free Radicals

59. Hydrogen atom abstraction from which position would yield the most stable free radical intermediate during the reaction of bromine with 2,2,3-trimethylpentane?

A) C1 B) C2 C) C3 D) C4 E) C5

Ans: C Topic: Free Radicals

60. Free radicals can be produced by: A) use of high temperatures. B) irradiation with light. C) reaction of a molecule with another free radical. D) both A) and B). E) all of A), B) and C).

Ans: E

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61. The ΔH° value is expected to be least for which indicated C-H bond of isopentane? A) CH2CHCH2CH3

CH3

H

B) CH3CHCH2CH3

CH2 H

C)

CH3CCH2CH3

CH3

H

D)

CH3CHCHCH3

CH3

H

E) CH3CHCH2CH2

CH3

H

Ans: C Topic: Free Radicals

62. Which is true for a chain-terminating step? A) A new free radical is formed. B) The process is endothermic. C) Eact = 0. D) ΔH° is positive. E) A product is formed which is immune to further reaction.

Ans: C Topic: Free Radicals

63. At some temperatures, the relative reactivities of 3°, 2° and 1° alkane hydrogens in free radical chlorination are in the ratio of 5:3:1. Thus, monochlorination of isopentane should produce these percentages of 2-chloro-2-methylbutane (A), combined 1-chloro-2-methylbutane and 1-chloro-3-methylbutane (B), and 2-chloro-3-methylbutane (C):

A) 8% A, 75% B, 17% C B) 25% A, 45% B, 30% C C) 29% A, 44% B, 18% C D) 30% A, 35% B, 35% C E) 36% A, 43% B, 21% C

Ans: B

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Topic: Miscellaneous

64. According to the present explanation of the role of atmospheric chlorofluorocarbons in ozone depletion, it is this species which destroys, i.e., reacts irreversibly with, ozone.

A) F· B) Cl· C) O· D) ClO· E) FO·

Ans: B Topic: Miscellaneous

65. If propene polymerization is initiated by the use of diacyl peroxide, this is an intermediate species formed early in the process.

A)

RCH2CHCH2CH

CH3 CH3

B)

RCHCH2CHCH2

CH3 CH3

C)

RCHCH2CH2CH

CH3 CH3

D)

RCH2CHCHCH2

CH3

CH3

E)

RCCH2CH

CH3

CH3CH3

Ans: A Topic: Miscellaneous

66. As the term "peroxide" is used in Chapter 10, it can refer to which structure(s)? A) ROOR B) ROOH C)

RCOOCR

O O

D) Answers A) and B) only E) Answers A), B) and C)

Ans: E

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67. When an alkane in which all hydrogen atoms are not equivalent is monosubstituted, use of this halogen produces a ratio of isomers which is essentially statistical, i.e., dependent only on the number of each type of hydrogen.

A) F2 B) Cl2 C) Br2 D) I2 E) All of the above

Ans: A Topic: Multistep Reactions

68. What is the final product, C, obtained via the following reaction sequence?

C

OH

A

OH OH OHOHOH

I II III IV V

Br2hν

i) BH3, THF

ii) H2O2, OH−Bt-BuOK

t-BuOHheat

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Multistep Reactions

69. What is the major product obtained from the following reaction sequence?

C

OH

A

OH OH OHOHOH

I II III IV V

Br2

hνi) Hg(OAc)2, H2O, THF

ii) NaBH4, OH−Bt-BuOK

t-BuOHheat

A) I B) II C) III D) IV E) V

Ans: B Topic: Multistep Reactions

70. What is the major product obtained from the following reaction sequence?

C

SH

A

SH SHSH

I II III IV V

Br2

hνHBrperoxidesBt-BuOK

t-BuOHheat

DNaSH

A) I B) II C) III D) IV E) V

Ans: A

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71. What is the major product obtained from the following reaction sequence?

C

CN

A

CN CN

CN

CNI II III IV V

DBr2

hνHBrperoxides

NaCNBEtONaEtOHheat

A) I B) II C) III D) IV E) V

Ans: C Topic: Multistep Reactions

72. What is the major product obtained from the following reaction sequence?

A

I II III

IV V

HBrperoxides C

i) BH3, THF

ii) H2O2, OH−B

OH OH

OH

OH

HO

t-BuOKt-BuOHheat

A) I B) II C) III D) IV E) V

Ans: E

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73. What is the major product obtained from the following reaction sequence?

CA

I II III IV V

Br2

hνi) O3ii) Zn, HOAc

O

O

B

OH

OH OH

O

O

EtONaEtOHheat

A) I B) II C) III D) IV E) V

Ans: E SHORT ANSWER QUESTIONS Topic: General 74. Intermediates possessing unpaired electrons are called ______________.

Ans: radicals or free radicals Topic: General

75. A covalent bond breaking so that each of the resulting intermediates bears a single unpaired electron is an example of __________________ bond cleavage. Ans: homolytic

Topic: General

76. Bond formation is an ______________ process, and therefore ΔH° is ____________. Ans: exothermic; negative

Topic: General

77. Although alkyl radicals are uncharged, the carbon bearing the odd electron is electron ___________, and alkyl groups provide a __________________ effect. Ans: deficient; stabilizing

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78. The mechanism for a free-radical reaction consists of three types of steps. These are: _______________ Ans: initiation, propagation, termination – or chain-initiating, chain-propagating, chain-

terminating Topic: General

79. In a chain-initiating step, radicals are _____________. Ans: created or formed

Topic: General

80. In a chain-terminating step, radicals are ______________. Ans: used up or removed

Topic: General

81. In a chain-propagating step, one radical _______________. Ans: generates another

Topic: General

82. While the electrophilic addition of HBr to an alkene is ionic and follows Markovnikov's rule, if the reaction is done in the presence of peroxides it becomes a ___________ reaction and is ____________________ in regiochemistry. Ans: radical or free-radical; anti-Markovnikov

Topic: General

83. Macromolecules made up of many repeating subunits are called ____________. Ans: polymers

Topic: General

84. Two radicals that are very important in biological processes are ________________ and __________________. Ans: molecular oxygen; nitric oxide

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Topic: General

85. Chlorofluorocarbons, or freons, diffuse into the upper atmosphere. There, ultraviolet light initiates a radical chain reaction that has been shown to cause extreme damage to _______________. Ans: the ozone layer

Topic: General

86. Unsymmetrical alkenes give Markovnikov products through the most stable_______________ intermediates and anti-Markovnikov products through the most stable _______________ intermediates. Ans: Carbocation; free-radical

Topic: Reaction Products ( Isomers)

87. Draw bond-line formulas of all monochloro derivatives that might be formed when 2,3-dimethylbutane is allowed to react with Cl2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Ans:

2,3-dimethylbutane

Cl2, hνCl

*Cl

+

monochloro derivatives Topic: Reaction Products ( Isomers)

88. Draw bond-line formulas of all monochloro derivatives that might be formed when 1,1-dimethylcyclobutane is allowed to react with Cl2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Ans:

monochloro derivatives1,1-dimethylcyclobutane

Cl2, hνCl+ +

ClCl *

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89. Draw bond-line formulas of all monochloro derivatives that might be formed when 3-ethylhexane is allowed to react with Cl2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Ans:

3-ethylhexane

Cl2 hν

+

monochloro derivatives

+Cl Cl

Cl

Cl

ClCl

* ** *

*

* ****

+

+

*

Cl

Topic: Structure Elucidation

90. Deduce the structure of a substance, C8H18, which gives only a single monochloro derivative upon reaction with Cl2 under UV irradiation. Ans:

C8H18

Cl2 hν

Cl

singlemonochloro derivative

Topic: Reaction Products ( Isomers)

91. Draw bond-line formulas of all dichloro derivatives that might be formed when 1-chloro-2,2,3,3,-tetramethylpentane is allowed to react with Cl2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Ans:

1-chloro-2,2,3,3-tetramethylpentane

Cl2 hν

dichloro derivatives

Cl ClCl

Cl

ClCl

Cl

Cl

Cl

ClCl

+ +

+

+

*

*

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92. Draw bond-line formulas of all monochloro derivatives that might be formed when 2,2,4-trimethylpentane is allowed to react with Cl2 under UV irradiation. For each structure, indicate, with an asterisk, any stereocenters that might be present. Ans:

2,2,4-trimethylpentane

Cl2 hν

monochloro derivatives

Cl +

+

+

Cl

Cl Cl

*

*

Topic: Multistep Reactions

93. Complete the following reaction sequence: indicate regiochemical/stereochemical details as relevant.

Methylcyclopentane

i) Br2, hν

ii) C2H5ONa/C2H5OH, heat

iii) BH3, THF

iv) H2O2, OH−

?

Ans: Br2

Br C2H5ONaC2H5OHheat

BH3, THF

H3C H

BH2

H +

H3C H

BH2

H H2O2, OH−H3C H

OH

H +

H3C H

OH

H

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Topic: Multistep Reactions

94. Complete the following reaction sequence: indicate regiochemical/stereochemical details as relevant.

i) Br2, hνii) C2H5ONa/C2H5OH, heat iii) HBr, peroxidesiv) NaCN

?

Ans: CN

BrBr2

hν Br

C2H5ONaC2H5OHheat

HBr peroxides

NaCN

Topic: Multistep Reactions

95. Complete the following reaction sequence: indicate regiochemical/stereochemical details as relevant.

i) Br2, hνii) C2H5ONa/C2H5OH, heat iii) Ozonolysis ?1,1,2-trimethylcyclohexane

Ans: Br2

hνC2H5ONaC2H5OHheat

Ozonolysis OOBr

Topic: Multistep Synthesis

96. Suggest a reasonable strategy for the synthesis of 1-bromo-2-methylcyclohexane from methylcyclohexane Ans: Br2

hν BrC2H5ONaC2H5OHheat

HBr peroxides Br

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97. Provide a reasonable mechanistic explanation for the formation of small amounts of 3,3,4,4-teramethylhexane during the free-radical bromination of 2-methylbutane. Ans: During the free radical bromination of 2-methylbutane, the most stable

intermediate is produced by abstraction of the tertiary hydrogen atom at C2. Two such radicals can couple together via a termination step to afford 3,3,4,4-teramethylhexane as a minor product.

Br2

+

minor product

termination step: radical coupling Topic: Mechanisms

98. What product(s) might be obtained via chain-termination step(s) during the reaction of 2-methylpropene with HBr in presence of peroxides? Ans: The addition of HBr to 2-methylpropene takes place via the formation of the most

stable free radical intermediate, by addition of a bromine atom at C1. Two such radicals can couple together via a termination step to afford 1,4-dibromo-2,2,3,3-teramethylbutane as a minor product. Analogous coupling between this radical and a bromine radical leads to the formation of 1,2-dibromo-2-methylpropane as another minor product.

HBrperoxides Br most stable radical intermediate

Br Br BrBr

+

Br + Br BrBr

termination steps: radical coupling

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99. Briefly, but clearly, explain the following observation: While alkanes can be fluorinated, chlorinated and brominated easily, they do not easily undergo iodination. Ans: The energy of activation for the first propagation step in the free radical

mechanism for halogenation of alkanes determines the overall reactivity pattern for the various halogens. In contrast to the reaction with the other halogens, hydrogen atom abstraction from an alkane by an iodine atom has a very high energy of activation- since this is the first propagation step, the overall process is affected as well and iodination does not occur to any appreciable extent. I . + R-H H-I + R . Eact for this step very high: reaction very slow, further steps inhibited

Topic: Reactivity / Selectivity

100. Briefly, but clearly, explain the following observation: When 2-methylbutane reacts with Cl2/hν, the monochlorinated products consist of four constitutional isomers in significant yields. However, when the same alkane is allowed to react with Br2/ hν, there is only one major monobromination product. Ans: The final product distribution is a consequence of the relative ease of hydrogen

atom abstraction from primary, secondary and tertiary positions. Chlorine is highly reactive and therefore there is not much differentiation between the different kinds of hydrogen atoms- as a result, all the possible free radicals are formed, leading to the formation of all possible constitutional isomers. Bromine is less reactive and more selective than chlorine in its reaction with alkanes; this results in the selective abstraction of the tertiary hydrogen atom at C2, to give the most stable radical intermediate, a tertiary radical, leading to the selective formation of only one major monobromination product.

Br2

Br

Cl2, hν

ClCl

ClCl

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MULTIPLE CHOICE QUESTIONS Topic: Nomenclature

1. What is the correct IUPAC name for the following compound? CH3

CH3CHOHCHCHCH(CH3)2

CH3A) 4-isopropyl-3,4-dimethyl-2-butanol B) 2,3,4-trimethyl-4-pentanol C) 1,1,2,3-tetramethyl-4-pentanol D) 3,4,5-trimethyl-2-hexanol E) 3,4,5,5-tetramethyl-2-pentanol

Ans: D Topic: Nomenclature

2. A correct IUPAC name for isobutyl alcohol is: A) 2-Methyl-1-propanol B) 2-Methyl-1-butanol C) 1-Methyl-1-propanol D) 1,1-Dimethyl-1-ethanol E) 3-Methyl-1-propanol

Ans: A Topic: Nomenclature

3. What is the correct IUPAC name for the following compound?

CH3CH2C=CCH2CH3

CH3

CH2CH2OH A) 3-methyl-4-ethyl-3-hexen-6-ol B) 4-ethyl-3-methyl-3,6-hexenol C) 3-ethyl-4-methyl-3-hexen-1-ol D) 3-methyl-4-(2-hydroxyethyl)-3-hexene E) 3-(2-hydroxyethyl)- 3-methyl-3-hexene

Ans: C

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4.

The correct IUPAC substitutive name for

CH3CCHCH

CH3

CH3

CH2

is: A) 4-Penten-2-methyl-2-ol B) 4-Methyl-1-penten-2-ol C) 2-Methyl-4-penten-2-ol D) 4-Methyl-1-penten-4-ol E) 4-Hydroxy-4-methyl-1-pentene

Ans: C Topic: Nomenclature

5. Which is a correct IUPAC name for CH3CH2OCH2CH2CH2OCH2CH3? A) 1,4-Dioxane B) Ethylene glycol diethyl ether C) 1,3-Diethoxypropane D) 1,2-Diethoxyethane E) 1,2-Diethoxymethane

Ans: C Topic: Nomenclature

6.

The IUPAC name of compound

CH3CH2COH

CH2CH3

CH2CH3

is: A) 1,1,1-Triethylmethanol B) 1,1-Diethyl-1-propanol C) 2-Ethyl-3-pentanol D) 3-Ethyl-3-pentanol E) tert-Heptanol

Ans: D

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7. The correct IUPAC name for tert-butyl alcohol is: A) 1-Butanol B) 2-Methyl-1-propanol C) 2-Methyl-2-propanol D) 2-Butanol E) 1,1-Dimethyl-1-ethanol

Ans: C Topic: Nomenclature

8. Select the structure of benzyl methyl ether.

O CH3CH3

CH3O

CH3 O CH2

CHCH3

O CHCH3

CH3 CH2 O CH2 CH3

I

II

III

IV

V

A) I B) II C) III D) IV E) V

Ans: C

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9.

OH

OH

is properly named: A) cis-1,2-Cyclopentanediol B) meso-1,2-Cyclopentanediol C) (1R,2R)-1,2-Cyclopentanediol D) (1R,2S)-1,2-Cyclopentanediol E) (1S,2S)-1,2-Cyclopentanediol

Ans: C Topic: Nomenclature

10. 2,2-Dimethyl-1-propanol has the common name: A) Isoamyl alcohol B) Isopentyl alcohol C) tert-Pentyl alcohol D) Neopentyl alcohol E) 2-Methylisobutyl alcohol

Ans: D Topic: Nomenclature

11. What is the most accurate name for the molecule represented by the following Fischer projection formula?

HOCH3

CH3

H3CH2C

A) sec-Butyl methyl ether B) Isobutyl methyl ether C) tert-Butyl methyl ether D) (R)-2-Methoxybutane E) (S)-2-Methoxybutane

Ans: E

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12. A correct name for the following Fischer projection formula is:

C CH3C

OH

H

CCH3

A) (R)-3-Pentyn-2-ol B) (S)-3-Pentyn-2-ol C) (R)-2-Pentyn-4-ol D) (S)-2-Pentyn-4-ol E) (S)-2-Hydroxy-3-pentyne

Ans: B Topic: Nomenclature

13. Which of these, though commonly used, is an incorrect name for CH3CHOHCH3? A) Isopropyl alcohol B) sec-Propyl alcohol C) 2-Propanol D) Isopropanol E) More than one of these.

Ans: D Topic: Nomenclature

14. Which of these, though commonly used, is an incorrect name for (CH3)3COH? A) tert-Butyl alcohol B) tert-Butanol C) 2-Methyl-2-propanol D) More than one is incorrect. E) Each is a correct name.

Ans: B Topic: Isomerism, Stereoisomers

15. Which of the following can be described as “optically active, primary alcohol”? A) CH3CH2CH2CH2CH2OH B) (CH3)2CHCH2CH2OH C) CH3CH2CH(CH3)CH2OH D) (CH3)2CHCHOHCH3 E) Two of the above

Ans: C

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16. What is the total number of pentyl alcohols, including stereoisomers? A) 7 B) 8 C) 9 D) 10 E) 11

Ans: E Topic: Isomerism, Stereoisomers

17. The number of primary alcohols corresponding to the formula C5H12O, counting stereoisomers separately, is:

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: E Topic: Isomerism, Stereoisomers

18. The number of optically active pentyl alcohols (C5H12OH), i.e., the total number of individual enantiomers, is:

A) 0 B) 2 C) 3 D) 4 E) 6

Ans: E Topic: Alcohol Reactions

19. Which of the following reactions would serve as a synthesis of butyl bromide? A) CH3CH2CH2CH2OH + HBr reflux

B) CH3CH2CH2CH2OH + PBr3 ⎯⎯⎯⎯⎯→ C) CH3CH2CH2CH2OH + NaBr reflux

D) CH3CH2CH2CH2OH + Br2 ⎯⎯⎯⎯⎯→ E) Answers A) and B) only

Ans: E

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20. The product(s) of the following reaction

CH2CH2

CH2

O

CH2

CH3CH2OCH2CH3 CH3CH2CH2CH2OH and CH3CH2CH2CH2Br

BrCH2CH2CH2CH2OH and BrCH2CH2CH2CH2Br

CHBrCH2

CH2

O

CH2

excess HBr

heatis/are:

I II

III IV

A) I B) II C) III D) IV E) None of these

Ans: C

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Topic: Alcohol Synthesis

21. Which product(s) would you expect to obtain from the following sequence of reactions?

CH3

CH3

OH

CH3

OH

CH3 H3C CH2OHO

OH

+enantiomer

+enantiomer

+enantiomer

I II III IV V

1. BH3-THF2. H2O2, NaOH

?

A) I B) II C) III D) IV E) V

Ans: C Topic: Alcohol Synthesis

22. Which would be the best way to carry out the following synthesis?

CH3CH2CHCH3

Br

CH3CH2CH2CH2OH?

A) (1) HA, heat; (2) H3O+, H2O, heat B) (1) (CH3)3COK / (CH3)3COH; (2) BH3:THF, then H2O2, OH- C) (1) (CH3)3COK / (CH3)3COH; (2) H3O+, then H2O, heat D) (1) KOH, C2H5OH; (2) BH3:THF, then H2O2, OH- E) (1) KOH, C2H5OH; (2) HA, heat; (3) H3O+, H2O, heat

Ans: B

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Topic: Alcohol Synthesis

23. Select the structure of the major product formed from the following reaction.

CH3

CH3OH

CH3

OH

CH2OH HO CH3CH3

OH

I II III IV V

1. Hg(OOCCH3)2 THF, H2O

2. NaBH4, NaOH?

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Alcohol Synthesis, Isotope Labeling

24. The hydroboration-oxidation procedure can be successfully employed for synthesis of deuterated derivatives, by using BD3 instead of BH3. What product would you expect from the following reaction?

CH3

CH3

DHOH CH3

DHH CH3

DBD2H CH3

OHDH CH3

BD2HD

1. (BD3)2

2. H2O2/NaOH?

+enantiomer

I

+enantiomer

II

+enantiomer

III

+enantiomer

IV

+enantiomer

VA) I B) II C) III D) IV E) V

Ans: A Topic: Ether Reactions, Isotope Labeling

25. Select the structure of the major product formed in the following reaction.

CH3CH

O

CH2 HA

H218O

?

A) CH3CH2CH218OH

B) CH3CHCH3

18OH

C) CH3CHCH2OH

18OH

D) CH3CH

OH

CH2

18OH

E) CH3CHCH218OH

18OH

Ans: C

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26. What would be the major product of the following reaction

C6H5CH2OCH3 ?

Concd. HBr (xs)

heatA) C6H5Br + CH3OH B) C6H5CH2Br + CH3Br C) C6H5CH2OH + CH3Br D) C6H5CH2Br + CH3OH E) C6H5CH2CH2Br

Ans: B Topic: Ether Synthesis

27. Which is the best way to prepare 3-methoxypentane via the Williamson method? A) CH3OH + CH3CH2CHOHCH2CH3 + H2SO4, 140°C B) CH3OH + (CH3)2CHCH2CH2OH + H2SO4, 140°C C) CH3ONa + (CH3CH2)2CHBr D) CH3I + (CH3CH2)2CHONa E) CH3I + (CH3)2CHCH2CH2ONa

Ans: D Topic: Ether Synthesis

28. Which is the best method to prepare 2-ethoxy-5methylhexane? A) C2H5ONa + (CH3)2CHCH2CH2Br B) C2H5ONa + (CH3)2CHCH2CH2CH2CH2Br C) C2H5ONa + (CH3)2CHCH2CH2CHBrCH3 D) C2H5Br + (CH3)2CHCH2CH2CH(CH3)ONa E) C2H5OH + (CH3)2CHCH2CH2CHOHCH3 + H2SO4, 140°C

Ans: D Topic: Alcohol Reactions

29. Which of the following could be used to synthesize 2-bromobutane? A) CH3CH2C=CH2 + Br2 (aq) ⎯⎯⎯⎯→ B) CH3CH2CΗΟΗCH3 + HBr ⎯⎯⎯⎯→ C) CH3CH2C≡CH + HBr ⎯⎯⎯⎯→ D) CH3CH2C≡CH + Br2 ⎯⎯⎯⎯→ E) More than one of the above

Ans: B

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30. Which of the following could not be used to synthesize 2-bromopentane efficiently? A) 1-Pentene + HBr B) 2-Pentene + HBr C) 2-Pentanol + HBr D) 2-Pentanol + PBr3 E) All of the above would afford good yields of 2-bromopentane

Ans: B Topic: Alcohol Reactions

31. Which of the following could be used to synthesize 1-bromobutane efficiently? A) CH3CH2CH=CH2 + HBr ⎯⎯⎯⎯→ B) CH3CH2CH2CH2OH + PBr3 ⎯⎯⎯⎯→ C) CH3CH2CH2CH2OH + HBr ⎯⎯⎯⎯→ D) CH3CH2CH2CH2OH + Br2 ⎯⎯⎯⎯→ E) More than one of these

Ans: E Topic: Alcohol Synthesis

32. Which of the following would be a reasonable synthesis of 2-butanol? A)

1-ButeneH3O+, heat

B) 1-Butene

2. H2O2, NaOH

1. BH3-THF

C) 1-Butene

2. NaBH4, NaOH

1. Hg(OAc)2, THF, H2O

D) More than one of these E) None of these

Ans: D

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33. What would be the final product?

H3CC CH2

CH3RCOOH

O

product final productCH3OH, HA

A) (CH3)2CHCH2OCH3 B) (CH3)2CCH3

OCH3

C) (CH3)2CCH2OH

OCH3

D) (CH3)2CCH2OCH3

OH

E) (CH3)2CCH2OCH3

OCH3

Ans: C Topic: Alcohol Synthesis

34. Which of the following would be a reasonable synthesis of CH3CH2CH2CH2OH? A)

1-ButeneH3O+, heat

B) 1-Butene

2. H2O2, NaOH

1. BH3-THF

C) 1-Butene

2. NaBH4, NaOH

1. Hg(OAc)2, THF, H2O

D) More than one of these E) None of these

Ans: B Topic: Alcohol Synthesis

35. Which would be the best method for converting 3,3-dimethyl-1-pentene into 3,3-dimethyl-2-pentanol?

A) H3O+, heat B) BH3:THF; then H2O2, OH- C) concd. H2SO4; then H2O, heat D) Hg(OAc)2/THF-H2O; then NaBH4,OH- E) HBr; then NaOH/H2O

Ans: D

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36. trans-3-Methylcyclopentanol is treated with CH3SO2Cl in the presence of base. The product of this reaction is then heated with KI in methanol. What is the final product?

A) trans-1-Iodo-3-methylcyclopentane B) cis-1-Iodo-3-methylcyclopentane C) 1-Methylcyclopentene D) 2-Methylcyclopentene E) 3-Methylcyclopentene

Ans: B Topic: Ether Synthesis

37. Which method would provide the best synthesis of ethyl isopropyl ether? A) (CH3)2CHONa + CH3CH2Br ⎯⎯⎯⎯⎯→ B) CH3CH2ONa + (CH3)2CHBr ⎯⎯⎯⎯⎯→ C)

CH3CH2OH + (CH3)2CHOHH2SO4, 140 oC

D) CH3CH2OH + (CH3)2CHOH

H2SO4, 180 oC

E) CH3CH2ONa + (CH3)2CHOH ⎯⎯⎯⎯⎯→ Ans: A

Topic: Alcohol Reactions

38. Which of the following could be used to synthesize 1-bromopentane? A) CH3CH2CH2CH=CH2 + HBr ⎯⎯⎯⎯→ B) CH3CH2CH2CH2CH2OH + PBr3 ⎯⎯⎯⎯→ C) CH3CH2CH2CH2CH2OH + NaBr ⎯⎯⎯⎯→ D) CH3CH2CH2CH2CH2OH + Br2 ⎯⎯⎯⎯→ E) CH3CH2CH2CH=CH2 + Br2 ⎯⎯⎯⎯→

Ans: B

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Topic: Epoxide Reactions

39. Which compound (or compounds) would be produced when trans-2-butene is treated first with a peroxy acid to form an epoxide, and then the epoxide is subjected to acid-catalyzed hydrolysis?

C

C

CH3HO

H CH3

H

OH

I

C

C

HHO

HO CH3

CH3

H

II

C

C

OHH

H3C H

CH3

OH

IIIA) An equimolar mixture of I and II B) An equimolar mixture of II and III C) I alone D) II alone E) III alone

Ans: E Topic: Ether Reactions

40. Heating 2-ethoxyhexane with excess concentrated HBr would produce: A) CH3CH2OCH2CH2CH2CH2CH2CH2Br B) BrCH2CH2OCH2CH2CH2CH2CH2CH3 C) CH3CH2OH and CH3CH2CH2CH2CHBrCH3 D) CH3CH2Br and CH3CH2CHOHCH2CH2CH3 E) CH3CH2Br and CH3CH2CH2CH2CHBrCH3

Ans: E Topic: Ether Synthesis

41. Which is the best method for the synthesis of tert-butyl methyl ether? A) CH3ONa + (CH3)3CBr ⎯⎯⎯⎯→ B) (CH3)3CONa + CH3I ⎯⎯⎯⎯→ C) CH3OH + (CH3)3COH + H2SO4 at 140° C ⎯⎯⎯⎯→ D) (CH3)3CONa + CH3OCH3 ⎯⎯⎯⎯→ E) CH3ONa + (CH3)3COH ⎯⎯⎯⎯→

Ans: B

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42. What would be the major product of the following reaction?

H

H

OH

CH3

H

H

I

CH3

I

H

H

CH3

H

I

I

CH3

H

H

OSO2I

CH3

CH3SO2Cl

basemesylate

NaI

ethanol?

I II III IV

A) I B) II C) III D) IV E) An equimolar mixture of I and II

Ans: B Topic: Alcohol Reactions

43. cis-3-Methylcyclopentanol is treated with CH3SO2Cl in the presence of a base. The product of the reaction then is allowed to react with KI in methanol. What is the final product?

A) trans-1-Iodo-3-methylcyclopentane B) cis-1-Iodo-3-methylcyclopentane C) 1-Methylcyclopentene D) 2-Methylcyclopentene E) 3-Methylcyclopentene

Ans: A

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Topic: Alcohol Reactions

44. The major product of the following reaction would be:

CH3SO2Cl

baseProduct ?

I II III

C2H5

H OHCH3

CH3CO2-

C2H5

H3CCO2 HCH3

C2H5

H O2CCH3

CH3

C2H5

H3CCO2 OSO2CH3

CH3

A) I B) II C) III D) Equal amounts of I and II E) None of these

Ans: A

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45. Which would be the major product of the reaction shown?

CH2CH3

H

CH2CH3OH

H

OH

CH2CH3H

H

H

CH2CH2OHH

H

H

CH2CH3H

OH

CH2CH3

H

2. NaBH4, NaOH

1. Hg(OAc)2, THF, H2O?

O

I II III IV V

A) I B) II C) III D) IV E) V

Ans: B Topic: Alcohol Reactions

46. Which reagent(s) would transform propyl alcohol into propyl bromide? A) Concd. HBr and heat B) PBr3 C) NaBr/H2O and heat D) More than one of these E) All of these

Ans: D

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Topic: Epoxide Reactions

47. Epoxidation followed by reaction with aqueous base converts cyclopentene into which of these?

I II III IV

H

OH

H

OH

H

OH

OH

H

H

OH

H

OH

OH

H

A) I B) II C) III D) IV E) Equal amounts of III and IV

Ans: E Topic: Ether Synthesis

48. When 3-methyl-2-pentene is treated with mercuric acetate, Hg(O2CCH3)2, in a THF-ethanol mixture and the resulting product reacted with NaBH4 in basic solution, the principal product formed is which of these?

A) 3-methyl-3-pentanol B) 3-ethoxy-3-methylpentane C) 3-methyl-2-pentanol D) 2-ethoxy-3-methylpentane E) 1-ethoxy-3-methylpentane

Ans: B Topic: Alcohol Synthesis

49. Anti-Markovnikov hydration of the carbon-carbon double bond occurs when an alkene reacts with:

A) BH3:THF; then H2O2/OH- B) BH3:THF; then CH3COOH C) Hg(OAc)2, THF, H2O; then NaBH4, OH- D) Hg(OAc)2, THF, CH3OH; then NaBH4, OH- E) Hg(OAc)2, THF, H2O; then BH3:THF

Ans: A

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Topic: Alcohol Reactions

50.

The conversion of

CH CH3CH

OH

H3C

CH3

to CH CH3CH

Br

H3C

CH3

is best achieved through use of which of these reagents in a low temperature reaction?

A) Concd. HBr B) Br2 C) NaBr, H2SO4 D) PBr3 E) HBr, peroxide

Ans: D Topic: Alcohol Reactions

51. The conversion of 3-methyl-1-octanol to 1-chloro-3-methyloctane is best achieved through use of which of these reagents?

A) Concd. HCl B) SO2Cl2 C) NaCl, H2SO4 D) PCl3 E) SOCl2

Ans: D Topic: Alcohol Reactions

52. What is the product of the reaction of propyl alcohol with (CH3)3SiCl in the presence of a tertiary amine?

A) CH3CH2CH2Si(CH3)3 B) (CH3)2CHSi(CH3)3 C) CH3CH2CH2OSi(CH3)3 D) (CH3)2CHOSi(CH3)3 E) (CH3CH2CH2)3SiOH

Ans: C

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Topic: Alcohol Synthesis

53. What is the major product of the reaction:

i) BH3, THFii) H2O2,NaOH

CH3

CH3

OH OH

CH3

I II III IV

CH3OH

?

+enantiomer

+enantiomer

A) I B) II C) III D) IV E) Both III and IV

Ans: D Topic: Alcohol Synthesis

54. What is the major product of the reaction when (R)-3-methylcyclohexene is subjected to the hydroboration-oxidation sequence?

A) (1R,2R)-2-methylcyclohexanol + (1S,2R)-2-methylcyclohexanol B) (1S,2R)-2-methylcyclohexanol + (1S,2S)-2-methylcyclohexanol C) (1R,3R)-3-methylcyclohexanol + (1S,3R)-3-methylcyclohexanol D) (1S,3R)-3-methylcyclohexanol (1S,3S)-3-methylcyclohexanol E) Two of the above

Ans: E

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Topic: Alcohol Synthesis

55. Oxymercuration-demercuration of 3-methylcyclopentene produces this/these product(s):

I II III IV

HO CH3CH2OH CH3 CH3

OH

OH

A) I B) II C) III D) IV E) Both III and IV

Ans: E

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Topic: Alcohol Reactions

56.

Methanesulfonic acid,

S

O

OH,

O

CH3

is treated, in turn, with PCl5 and (R)-2-butanol. Which of the following Fischer formulas is a stereochemically correct representation of the final product?

S

O

O

I II III

IV V

O

CH3 C

CH3

CH2

H

CH3

S

O

O

CH3 C

CH3

CH2

H

CH3

S

O

O

O

CH3 C

H

CH2

CH3

CH3

S

O

O

CH3 C

H

CH2

CH3

CH3

S

O

O

CH3 C

CH3

CH2

Cl

CH3

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Epoxide Reactions

57. cis-3-Hexene is treated with magnesium monoperoxyphthalate and the product is then subjected to acid-catalyzed hydrolysis. What is the final product?

CH2CH3

CH2CH3

HHOHH

I II

CH2CH3

CH2CH3

HHHHO

CH2CH3

CH2CH3

OHHHHO

III IV

CH2CH3

CH2CH3

HHOOHH

V

CH2CH3

CH2CH3

OHHOHH

A) equal amounts I and II B) equal amounts I, II and V C) equal amounts III, IV and V D) equal amounts, III and IV E) Only V

Ans: D Topic: Chemical Tests

58. Which of the following reagents might serve as the basis for a simple chemical test that would distinguish between pure 1-butene and CH3CH2CH2CH2OH?

A) Bromine in carbon tetrachloride B) Dilute aqueous potassium permanganate C) Chromic oxide in aqueous sulfuric acid D) All of these E) None of these

Ans: D Topic: Chemical Tests

59. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between

Oand ?

A) AgNO3 in alcohol B) NaOH in H2O C) Br2 in CCl4 D) Cold concd. H2SO4 E) KMnO4 in H2O

Ans: D

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60. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between

Oand

Br?

A) AgNO3 in C2H5OH B) Dilute HCl C) Br2 in CCl4 D) NaOH in H2O E) KMnO4 in H2O

Ans: A Topic: Physical Properties, Comparison

61. Which of the compounds listed below would you expect to have the highest boiling point? (They all have approximately the same molecular weight.)

A) CH3CH2CH2CH2CH3 B) CH3CH2CH2CH2OH C) CH3CH2CH2OCH3 D) CH3CH2CH2Cl E) CH3CH2OCH2CH3

Ans: B Topic: Physical Properties, Comparison

62. Which compound would have the highest boiling point? A) CH3CH2CH2CH3 B) CH3CH2OCH3 C) CH3CH2CH2OH D) (CH3)2CHOH E) HOCH2CH2OH

Ans: E Topic: Physical Properties, Comparison

63. Which compound would have the lowest solubility in water? A) Diethyl ether B) Methyl propyl ether C) 1-Butanol D) 2-Butanol E) Pentane

Ans: E

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Topic: Physical Properties, Comparison

64. Which compound would have the lowest boiling point?

I II III IV V

OOH

OH CH2OHOH

A) I B) II C) III D) IV E) V

Ans: A Topic: Physical Properties, Comparison

65.

Which compound would have the highest boiling point?

I II III

IV V

O

O

OH

OH

O

OH

O O O O

A) I B) II C) III D) IV E) V

Ans: E Topic: Alcohol Reaction Rates

66. Which of the alcohols listed below would you expect to react most rapidly with HBr? A) CH3CH2CH2CH2CH2CH2OH B) (CH3CH2)2CH2CH2OH C) (CH3CH2)2CHOHCH3 D) CH3CH2CH2CH2CH2OH E) (CH3CH2)2C(CH3)OH

Ans: E

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Topic: Alcohol Reaction Rates

67. Which alcohol would undergo acid-catalyzed dehydration most rapidly? A) 3,3-dimethyl-1-butanol B) 2,2-dimethyl-1-butanol C) 3,3-dimethyl-2-butanol D) 2-methyl-2-butanol E) All would undergo dehydration equally rapidly.

Ans: D Topic: Ether Reaction Rates

68. Which of these ethers is most resistant to peroxide formation on exposure to atmospheric oxygen?

A) CH3OCH2CH3 B) CH3CH2OCH2CH3 C) (CH3)2CHOCH(CH3)2 D) (CH3)2CHOCH2CH3 E) CH3OC(CH3)3

Ans: E Topic: Ether Reaction Rates

69. Which of these ethers is least likely to undergo significant cleavage by hot aqueous H2SO4 ?

I II III

IV V

CH3OCH3 CH3OCH(CH3)2 (CH3)2CHOCH(CH3)2

(CH3)3COC(CH3)3 O

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Alcohol Reaction Rates

70. Which of these alkyl halide syntheses is predicted to occur at the greatest rate? A) CH3CH2CH2CH2OH + HI ⎯⎯⎯⎯→ B) (CH3)2CHCH2OH + HBr ⎯⎯⎯⎯→ C) CH3CHOHCH2CH3 + HCl ⎯⎯⎯⎯→ D) CH3CHOHCH2CH3 + HBr ⎯⎯⎯⎯→ E) (CH3)3COH + HI ⎯⎯⎯⎯→

Ans: E Topic: Reaction Mechanisms

71. The following reaction,

CH3CH2CH2CH2OH CH3CH2CH2CH2Br + H2O

HBr

heat

is probably: A) An SN1-type reaction involving the protonated alcohol as the substrate. B) An SN2-type reaction involving the protonated alcohol as the substrate. C) An E1-type reaction involving the protonated alcohol as the substrate. D) An E2-type reaction involving the protonated alcohol as the substrate. E) An epoxidation reaction.

Ans: B Topic: Reaction Mechanisms

72. The reaction between 1-pentanol and HBr to yield 1-bromopentanol is probably:

A) an SN1-type reaction involving the protonated alcohol as the substrate. B) an SN2-type reaction involving the protonated alcohol as the substrate. C) an E1-type reaction involving the protonated alcohol as the substrate. D) an E2-type reaction involving the protonated alcohol as the substrate. E) an epoxidation reaction.

Ans: B Topic: Reaction Mechanisms

73. The reaction between 2-methyl-2-pentanol and HBr to yield 2-bromo-2-methylpentane is probably:

A) an SN1-type reaction involving the protonated alcohol as the substrate. B) an SN2-type reaction involving the protonated alcohol as the substrate. C) an E1-type reaction involving the protonated alcohol as the substrate. D) an E2-type reaction involving the protonated alcohol as the substrate. E) an epoxidation reaction.

Ans: A

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74. The reaction between 2-methyl-2-pentanol and HBr to yield 2-methyl-2-pentene is probably:

A) an SN1-type reaction involving the protonated alcohol as the substrate. B) an SN2-type reaction involving the protonated alcohol as the substrate. C) an E1-type reaction involving the protonated alcohol as the substrate. D) an E2-type reaction involving the protonated alcohol as the substrate. E) an epoxidation reaction.

Ans: C Topic: Reaction Mechanisms

75. The reaction between 4-methyl-1-pentanol and HBr to yield 4-methyl-1-pentene is probably:

A) an SN1-type reaction involving the protonated alcohol as the substrate. B) an SN2-type reaction involving the protonated alcohol as the substrate. C) an E1-type reaction involving the protonated alcohol as the substrate. D) an E2-type reaction involving the protonated alcohol as the substrate. E) an epoxidation reaction.

Ans: D Topic: Reaction Mechanisms

76. Which statement is true concerning the formation of alcohols by the hydroboration-oxidation sequence?

A) Overall, the process results in syn addition and anti-Markovnikov orientation. B) Overall, the process results in anti addition and anti-Markovnikov orientation. C) Overall, the process results in syn addition and Markovnikov orientation. D) Overall, the process results in anti addition and Markovnikov orientation. E) The stereochemistry and orientation are unpredictable.

Ans: A

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Topic: Reaction Mechanisms

77. What is the electrophilic species involved in the initial step of the reaction below?

OHHgOAc

Hg(OAc)2

THF, H2OA) +OH B) +HgOAc C) H3O+ D) THF E) the THF/H2O complex

Ans: B Topic: Reaction Mechanisms

78. The following reaction,

2 CH3CH2CH2CH2OH (CH3CH2CH2CH2)2O + H2O

H2SO4

heat

is probably: A) an SN1-type reaction involving the protonated alcohol as the substrate. B) an SN2-type reaction involving the protonated alcohol as the substrate. C) an E1-type reaction involving the protonated alcohol as the substrate. D) an E2-type reaction involving the protonated alcohol as the substrate. E) an epoxidation reaction.

Ans: B Topic: Stereoisomerism

79. What is the relationship between alcohols I and II?

H

CH3OH

H

H

CH3H

OH

I II

They are: A) different conformations of the same compound. B) constitutional isomers. C) enantiomers. D) diastereomers. E) identical.

Ans: D

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Topic: Stereoisomerism

80. What is the relationship between alcohols I and II?

H

CH3OH

H

CH3

HH

OH

I II

They are: A) different conformations of the same compound. B) constitutional isomers. C) enantiomers. D) diastereomers. E) identical.

Ans: C Topic: Ether Reactivity

81. Which of the following statements is NOT true of ethers? A) Ethers are generally unreactive molecules toward reagents other than strong acids. B) Ethers generally have lower boiling points than alcohols of a corresponding molecular

weight. C) Ethers generally have much lower water solubilities than alcohols with a corresponding

molecular weight. D) Ethers can generally be cleaved by heating them with strong acids. E) Ethers form peroxides when allowed to stand in the presence of oxygen.

Ans: C

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Topic: General

82. Which compound is a tosylate?

CH3 S O

O

O

CH3 Br S O

O

O

CH2 CH3 S O

O

CH3

CH3 S CH3

O

CH3 S

O

O

CH3

CH3

O

I II III

IV VA) I B) II C) III D) IV E) V

Ans: A Topic: General

83. The major industrial process in use today for the production of methanol is the: A) hydration of ethyne. B) distillation of wood. C) hydrogenation of carbon dioxide. D) reduction of methanal. E) catalytic reduction of carbon monoxide.

Ans: E Topic: General

84. Today, most industrial ethanol is made in the U.S. by the: A) fermentation of grain. B) hydrolysis of ethyl bromide. C) hydration of ethylene. D) reduction of acetaldehyde. E) hydration of acetylene.

Ans: C

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Topic: Ether Reactivity

85. Long-term storage of ethers can be dangerous, because most ethers react slowly with oxygen by a radical process called __________________. This process forms peroxides and hydroperoxides which are dangerously _______________. Ans: autooxidation, explosive

Topic: General, Alcohol Synthesis

86. We have learned three different methods to convert alkenes into alcohols. a. The method that takes place with Markovnikov regioselectivity but is prone to rearrangement is ________________. b. The method that takes place with Markovnikov regioselectivity and does not lead to rearrangement is _____________. c. The method that takes place with anti-Markovnikov regioselectivity and syn stereoselectivity is _______________. Ans: a. acid-catalyzed hydration; b. oxymercuration-demercuration; c. hydroboration-

oxidation Topic: General, Alcohol Reactions

87. Reactions of alcohols can be broadly categorized into three types. a. Those that utilize the hydroxyl oxygen as a ____________. b. Those that utilize the hydroxyl proton as an _________. c. Those that convert the hydroxyl group into a _____________. Ans: a nucleophile or base; b. acid; c. leaving group

Topic: General

88. Stereochemically speaking, conversion of an alcohol into a tosylate occurs with _____________ of configuration. Ans: retention

Topic: General

89. When an alcohol in which the OH is attached to a stereogenic carbon reacts with thionyl chloride (SOCl2) in the presence of a 3° amine, the resulting alkyl chloride is produced with _____________ of configuration. Ans: inversion

Topic: General

90. The SN2 reaction between an alkoxide and an alkyl halide is commonly referred to as the _________________ synthesis. Ans: Williamson

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91. Three-membered rings containing oxygen are called _______________ or ______________. Ans: oxiranes; epoxides

Topic: General

92. The development of a procedure called __________________ has made the use of nonpolar solvents possible in reactions involving polar reagents. Ans: phase transfer catalysis

Topic: General

93. The relationship between a crown ether and the ion it transports is known as the ____________________ relationship. Ans: host-guest

Topic: General

94. A compound or ion that prefers a nonpolar environment to an aqueous one is said to be ______________. Ans: lipophilic

Topic: Isomerism

95. Draw structures for all possible ethers having the formula C4H10O Ans:

C4H10O: ethers

O OO

Topic: Ether Synthesis

96. Which is the most efficient way to prepare isopropyl methyl ether via the Williamson method? Ans: CH3I + (CH3)2CHONa

Topic: Ether Synthesis

97. Which is the best method to prepare ethoxycyclopentane via the Williamson method? Ans: ONa I

O+

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Topic: Alcohol Synthesis

98. Draw the structures of all the products formed when (3R)-3-methylcyclopentene is subjected to the hydroboration-oxidation sequence. Ans: The alkene is symmetrically substituted: thus, Markovnikov rule does not apply.

Hence, all four products shown below are likely to be formed in roughly equal proportions.

H3C H

(3R)-3-methylcyclopentene

hydroboration-oxidation

H3C H H3C H H3C H H3C HOH OH

OH OH+ + +

Topic: Ether Synthesis

99. Provide a reasonable synthetic strategy for the synthesis of trans-1,2-cyclohexanediol from bromocyclohexane Ans: CH3ONa

CH3OHheat

Br MMPPO H3O+ OH

OH +enantiomer

Topic: Nomenclature

100. Give the correct IUPAC name corresponding to the following structure:

OH Ans: 6-cyclohexyl-2,7-dimethyl-3-octanol

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Topic: Nomenclature

101. Give the correct IUPAC name corresponding to the following structure:

OH

Ans: (R)-3-ethyl-2-methyl-3-hexanol

Topic: Nomenclature

102. Give the correct IUPAC name corresponding to the following structure:

O O Ans: 1,3-diethoxyhexane

Topic: Nomenclature

103. Give the correct IUPAC name corresponding to the following structure:

CH3

OH

Br H

Ans: (1R,2R)-2-bromo-1-methylcyclopentanol

Topic: Multistep Synthetic Strategy

104. Provide a reasonable synthetic strategy for the synthesis of a racemic mixture of (1R,2R) and (1S,2S)-2-bromo-1-methylcyclopentanol from methylcyclohexane. Ans:

CH3

OH

Br H

CH3

BrBr2

hνCH3ONaCH3OHheat

CH3

OH

Br H

+

Br2, H2O

2-bromo-1-methylcyclopentanol(1R,2R) (1S,2S)

CH3CH3

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Topic: Multistep Reactions

105. Complete the following reaction sequence, giving structural details of all key intermediates:

i) Li, NH3

ii) KMnO4 ,OH−, H2O

iii) H3O+

?

Ans: LiNH3

i) KMnO4 ,OH−, H2O

ii) H3O+

OH

H

H

HO

OH

H

H

HO

+

2S,3R 2R,3S Topic: Multistep Reactions

106. Complete the following reaction sequence, giving structural details of all key intermediates:

i) H2, Lindlar catalyst

ii) KMnO4 ,OH−, H2O

iii) H3O+

?

Ans: i) KMnO4 ,OH−, H2O

ii) H3O+

OH

H

H

HO

meso

H2 Lindlar catalyst

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Topic: Multistep Reactions

107. Complete the following reaction sequence, giving structural details of all key intermediates:

i) Li, NH3

ii) MMPP

iii) H3O+, H2O

?

Ans: LiNH3

OH

OH

H

H

OH

OH

H

H

+

2S, 3S 2R, 3R

i) MMPP

ii) H3O+, H2O

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MULTIPLE CHOICE QUESTIONS Topic: General Carbonyl Information

1. Which of the following resonance structures is not a significant contributor to the hybrid for the carbonyl group?

C O C O C O

I II IIIA) I B) II C) III D) Neither II nor III is important. E) All are significant contributors.

Ans: B Topic: General Carbonyl Information

2. When nucleophilic addition to a carbonyl group occurs, the carbon attacked undergoes this hybridization change:

A) sp2 ⎯⎯⎯⎯→ sp3 B) sp ⎯⎯⎯⎯→ sp2 C) sp ⎯⎯⎯⎯→ sp3 D) sp3 ⎯⎯⎯⎯→ sp2 E) sp2 ⎯⎯⎯⎯→ sp

Ans: A Topic: Functional Group Tests

3. Which reagent(s) will distinguish between cyclopentanol and cyclopentane? A) Br2/CCl4 B) KMnO4 (cold) C) CrO3/aqueous H2SO4 D) NaOH (aq) E) A) and B)

Ans: C

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Topic: Functional Group Tests

4. Which reagent(s) will distinguish between 2-methylcyclopentanol and 1-methylcyclopentanol?

A) Br2/CCl4 B) KMnO4 C) CrO3/aqueous H2SO4 D) NaOH (aq) E) B) and C)

Ans: E Topic: Functional Group Tests

5. Which of the following reagents might serve as the basis for a simple chemical test that would distinguish between CH3CH=CHCH3 and CH3CHOHCH2CH3?

A) CrO3 in H2SO4 B) KMnO4 C) Br2 in CCl4 D) Two of these E) All of these

Ans: D Topic: Functional Group Tests

6. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between CH3CH=CHCH2OH and CH3CH2CH2CH2OH ?

A) CrO3 in H2SO4 B) Cold conc. H2SO4 C) Br2 in CCl4 D) NaOH/H2O E) NaBH4

Ans: C Topic: Functional Group Tests

7. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between (CH3)2C=CHCH2CH2OH and (CH3)2CHCH2CH2CH2OH ?

A) CrO3 in H2SO4 B) Cold conc. H2SO4 C) Br2 in CCl4 D) NaOH/H2O E) NaBH4

Ans: C

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Topic: Functional Group Tests

8. Which of the reagents/techniques listed below would serve as the basis for a simple chemical test to distinguish between 2-methyl-3-hexyn-1-ol and 2-methyl-5-hexyn-1-ol?

A) CrO3 in H2SO4 B) Cold conc. H2SO4 C) Br2 in CCl4 D) NaBH4 E) IR spectroscopy

Ans: E Topic: Functional Group Tests

9. Which of the reagents/techniques listed below would serve as the basis for a simple chemical test to distinguish between 2-methyl-3-hexyn-2-ol and 2-methyl-5-hexyn-1-ol?

A) CrO3 in H2SO4 B) IR spectroscopy C) Br2 in CCl4 D) A) and B) E) All of the above

Ans: D Topic: Functional Group Tests

10. Which of the reagents/techniques listed below would serve as the basis for a simple chemical test to distinguish between CH3CH2CH=CHCH2CH2CHO and CH3CH2CH=CHCH2CH2CH2OH?

A) KMnO4 B) IR spectroscopy C) Br2 in CCl4 D) A) and B) E) All of the above

Ans: B Topic: Functional Group Tests

11. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between (CH3)3COH and (CH3)2CHCH2OH ?

A) NaH B) NaOH/H2O C) Br2 in CCl4 D) Cold conc. H2SO4 E) CrO3 in H2SO4

Ans: E

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Topic: Functional Group Tests

12. CrO3 in H2SO4/H2O will fail to give a positive test with which of these compounds? A) CH3CH2CH2CH2OH B) CH3CHCH2CH3

OH

C) (CH3)3COH D)

CH3CH2CH2C O

H

E) More than one of these Ans: C

Topic: Functional Group Tests

13.

Consider the molecule CH3CHC CHCH2OH.

CH3

Which reagent will not give a positive test with this compound? A) Cold conc. H2SO4 B) Br2/CCl4 C) NaOH (aq) D) CrO3/H2SO4 E) Dilute KMnO4/H2O

Ans: C

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Topic: Reactions and Reaction Sequences

14. The final product, D, in the following reaction sequence,

CH3CHOH

CH3

CH2

O

CH2

PBr3 Aether

B CH3O+

DMg

, would be?

A) CH3CHOCH2CH2OH

CH3

B) CH3CHCH2CH2Br

CH3

C) CH3CHCH2CH2OH

CH3

D) CH3CHOCH2CH3

CH3

E) CH3CHCH2CH3

CH3

Ans: C

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Topic: Reactions and Reaction Sequences

15. What is the product, A, that would be obtained from the following reaction sequence?

CH3CH

O

CHCH3CH3CH2MgBr H3O+

C CH A

C CCH2CH3 C CCH

CH3

CHOCH2CH3

CH3

C CCH

CH3

CHOH

CH3

CH3CH2

C CCH

CH3

CHOH

CH3

C C CHCH2CH3

CH3

O

I II III

IV VA) I B) II C) III D) IV E) V

Ans: D

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16. What is the product, A, that would be obtained from the following reaction sequence?

CH2

O

CH2

CH3CH2MgBr H3O+

C CH A

C CCH2CH3 C CCH2CH2OCH2CH3 C CCH2CH2OHCH3CH2

C CCH2CH2OCH3 C COCHCH2CH3

I II III

IV V

CH3

A) I B) II C) III D) IV E) V

Ans: C Topic: Reactions and Reaction Sequences

17. What would be the product, C, of the following reaction sequence?

CH3CCH2Br

CH3

CH3

etherA

CuIB

CH3CHCH2CH2Br

CH3

CLi

A) 2,6-Dimethylheptane B) 2,2-Dimethylpropane C) 2-Methylpentane D) 2,2,5-Trimethylhexane E) 2,2,6-Trimethylheptane

Ans: E

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Topic: Reactions and Reaction Sequences

18. What would be the product, O, of the following reaction sequence?

CH3CH2CHCH3

Br etherN

D2OO

Mg

A) CH3CH2CH2CH3 B) CH3CH2CHCH3

D

C) CH3CH2CHCH3

OD

D) CH3CH2CH2CH2OD E) CH3CH2CH2CH2D

Ans: B Topic: Reactions and Reaction Sequences

19. What is the product, A, that would be obtained from the following reaction sequence?

PBr3 Li NH4Cl

10oC(CH3)2C=OOH

I II

IV V

OHOH

HO

III

A

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Reactions and Reaction Sequences

20.

What is the product, A, that would be obtained from the following reaction sequence?

PBr3 Mg, Et2O H3O+ heat

(CH3)2C=OOH

I II

IV V

OHOH

HO

III

A

A) I B) II C) III D) IV E) V

Ans: C Topic: Reactions and Reaction Sequences

21. What would be the final product, A, in the following reaction sequence?

PBr3 Mg, Et2O H3O+ heat

IV V

I II III

O OH

OH

BrO

OH

OHO

A

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Reactions and Reaction Sequences

22. What is the final product of the following reaction sequence?

Mg, Et2O

O

O

O

IV V

I II III

OH

OH O

O

ii) H3O+CH3I H2CrO4

acetoneA

i)

A) I B) II C) III D) IV E) V

Ans: E

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Topic: Reactions and Reaction Sequences

23. What would be the alkane C that is the product of the following reaction sequence?

CH3CHBr

CH3ether

ACuI

BCH3CHCH2Br

CH3

CLi

A)

CH3CHCHCH2CH3

CH3

CH3

B) CH3CH CHCH2CH3

CH3 CH3

C)

CH3CHCH2CHCH3

CH3

CH3

D)

CH3CH CCH3

CH3 CH3

CH3

E)

CH3CH2CH2CH2CHCH3

CH3

Ans: C

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Topic: Reactions and Reaction Sequences

24. What would be the major product of the following reaction?

O O

III

IV V

OHO OH O

OH

O OH

I II

HO O OH

O Ai) NaBH4 ii) ethylene oxide, HA

A) I B) II C) III D) IV E) V

Ans: A Topic: Reactions and Reaction Sequences

25. What would be the major product of the following reaction?

O

S OO

OCH2CH3

Ai) NaBH4 ii) NaH, Et2Oiii)

A) CH3CH2OCH(CH3)CH2CH2CH2CH3 B) (CH3CH2O)2CHCHOHCH2CH2CH3 C) (CH3CH2)2CHOHCH2CH2CHOHCH3 D) CH3OCH(C2H5)CH2CH2CH2CH3 E) CH3CH2CH(OCH3)CH2CH2CHOHCH3

Ans: A

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Topic: Reactions and Reaction Sequences

26.

What would be the major product of the following reaction?

Li, Et2O ABr

CH3Cl

HCuI

A) (R)-3-ethyl-5-methylheptane B) (R,S)-3-ethyl-5-methylheptane C) (S)-3-ethyl-5-methylheptane D) (3R,5S)-5-ethyl-3-methylheptane E) (3S,5R)-5-ethyl-3-methylheptane

Ans: C Topic: Reactions and Reaction Sequences

27. What is the principal product(s) formed when 1 mol of methylmagnesium iodide reacts with 1 mol of p-hydroxyacetophenone ?

CH3MgI

IV V

I II IIIIMgO

O

OMgI

HO

O

O MgI IMgO

O

O

O

HO

O

A

+ CH4

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Reactions and Reaction Sequences

28.

What is (are) the principal product(s) formed when 1 mol of ethylmagnesium bromide reacts with 1 mol of 3-(N-methylamino)cyclopentanone ?

CH3CH2MgBr

IV V

I II III

OHN

H3C

OBrMgNCH3 H

NH3C

CH2CH3

OMgBr

ONH3C

H3CH2COMgBr

HN

H3C

CH2CH3

A

OHN

H3C CH2CH3+ CH4

A) I B) II C) III D) IV E) V

Ans: A Topic: Reactions and Reaction Sequences

29.

What would be the product, A, of the following reaction ?

OA

i) NaBD4 ii) H2O

A)

OD B)

OHD

C) ODD

D) OH

E) O

D

Ans: B

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30. What is the predominant product from the reaction of 2-hexanol with H2CrO4? A) CH3CO2H B) CH3(CH2)3CO2H C)

CH3(CH2)3CCH3

O

D) CH3(CH2)4CO2H E) A) and B)

Ans: C Topic: Synthetic Strategy, Redox 31. Which of the reagents listed below would efficiently accomplish the transformation of

CH3CH2CH=CHCH2CH2CHO into CH3CH2CH=CHCH2CH2CH2OH? A) KMnO4 B) NaBH4 C) Br2 in CCl4 D) H2, Ni E) Two of the above

Ans: B Topic: Synthetic Strategy, Redox 32. Which of the reagents listed below would efficiently accomplish the transformation of

CH3CH2CH=CHCH2CH2CHO into CH3CH2CH2CH2CH2CH2CH2OH? A) KMnO4 B) NaBH4 C) Br2 in CCl4 D) H2, Ni E) Two of the above

Ans: D Topic: Synthetic Strategy, Redox 33. Which of the reagents listed below would efficiently accomplish the transformation of

CH3CH2C≡CCH2CH2CHO into CH3CH2C≡CCH2CH2CH2OH? A) KMnO4 B) NaBH4 C) Br2 in CCl4 D) H2, Ni E) Two of the above

Ans: B

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414

Topic: Synthetic Strategy, Redox

34. Which of the reagents listed below would efficiently accomplish the transformation of CH3CH2CH=CHCH2CH2CH2OH into CH3CH2CH=CHCH2CH2CHO ?

A) KMnO4(aq, alkaline) B) CrO3 / H2SO4 C) PCC in CH2Cl2 D) Br2, CCl4 E) Two of the above

Ans: C Topic: Synthetic Strategy

35. Which of the reagents listed below would efficiently accomplish the transformation of 2-methyl-3-cyclopentenol into 2-methyl-3-cyclopentenone?

OH O?

A) KMnO4(aq, alkaline) B) CrO3/H2SO4 C) H2, Pt D) Br2, CCl4 E) Two of the above

Ans: B Topic: Synthetic Strategy, Redox

36. Which of the reagents listed below would efficiently accomplish the transformation of 3-methyl-3-cyclopentenone into 3-methyl-3-cyclopentenol?

O OH?

A) i) LiAlH4; ii) H2O B) NaBH4,H2O C) H2, Pd D) A) and B) E) A), B) and C) of the above

Ans: D

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37. Which of the reagents listed below would efficiently accomplish the transformation of ethyl-3-pentenoate into 3-penten-1-ol?

?O

O

HO

A) i) LiAlH4; ii) H2O B) NaBH4,H2O C) H2, Pd D) A) and B) E) A), B) and C) of the above

Ans: A Topic: Reactions and Reaction Sequences

38. When 2-pentanol is treated with chromic acid, A) The color changes from orange to blue B) The color changes from purple to colorless C) The color changes from blue to red D) The color changes from orange to green E) The color changes from green to orange

Ans: D Topic: Reactions and Reaction Sequences

39. When 1-pentanol is treated with alkaline potassium permanganate, A) The color changes from orange to blue B) The color changes from purple to colorless C) The color changes from blue to red D) The color changes from orange to green E) The color changes from green to orange

Ans: B Topic: Reactions and Reaction Sequences

40. When 3-methyl-3-pentanol is treated with chromic acid, A) The color changes from orange to blue B) The color changes from purple to colorless C) The purple color remains unchanged D) The color changes from orange to green E) The orange color remains unchanged

Ans: E

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Topic: Reactions and Reaction Sequences

41. What is the final product?

NaNH2 CH3I?

CH3CCH3

O

CH3C CHliq. NH3

A)

CH3CC

CH3

CCH3

HO

B)

CH3CC

CH3

CCH3

OCH3

C)

CH3C COCH2CHCH3

OCH3

D)

CH3CC

CH3

CONa

CH3

E) None of these Ans: B

Topic: Reactions and Reaction Sequences

42. What product(s) is/are formed in the following reaction?

D2OLiAlD4 ?etherCH3CH2CH2COCH2CH3

O

A) CH3CH2CH2CH2OD + CH3CH2OD B) CH3CH2CH2CD2OD + CH3CH2OD C) CH3CH2CH2CD2OH + CH3CH2OH D) CH3CH2CH2CHDOD + CH3CH2OD E)

CH3CH2CH2CDOCH2CH3

OD

Ans: B

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Topic: Reactions and Reaction Sequences

43. What product(s) is/are produced in the 1:1 reaction of sec-butylmagnesium bromide with

?

CH3CHCH2CH2C

HOH

O

A) CH3CHCH2CH2CHCCH2CH3

OMgBrOH

CH3

B)

CH3CHCH2CH2C

HOMgBr

O + CH3CH2CH2CH3C)

CH3CHCH2CH2CHCH2CH(CH3)2

OMgBrOH

D)

CH3CHCH2CH2C

HOMgBr

O + (CH3)3CHE)

CH3CHCH2CH2C

H

O

OCHCH2CH3

CH3

Ans: B

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Topic: Reactions and Reaction Sequences

44. What is the principal product of the following reaction:

CH3CH CH2

O

+ CH3CH2CH2CH2MgBr/ether; then H2O ⎯⎯⎯⎯→ ? A) CH3CHCH2CH2CH2CH3

CH2OH

B)

CH3CHCH2CH2CH2CH2CH3

OH

C)

CH3CHCH2OCH2CH2CH2CH3

OH

D) CH3CHOCH2CH2CH2CH3

CH2OH

E) CH3CHCH2OCH2CH2CH2CH3

OCH2CH2CH2CH3

Ans: B Topic: Reactions and Reaction Sequences

45. The reaction of lithium di-sec-butylcuprate with isopentyl bromide yields: A) 2,5-Dimethylheptane B) 2,6-Dimethylheptane C) 3,5-Dimethylheptane D) 3,4-Dimethylheptane E) 3,6-Dimethylheptane

Ans: A Topic: Reactions and Reaction Sequences

46. The reaction of lithium diethylcuprate with 1-bromo-4,4-dimethylhexane yields: A) 3,3-Dimethylheptane B) 3,3-Dimethyloctane C) 1-Ethyl-4,4-dimethylhexane D) Di-4,4-dimethylhexylcuprate E) None of the above

Ans: B

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Topic: Reactions and Reaction Sequences

47. What compound(s) result(s) from the reaction of CH3CH2CH2MgBr with CH3CH2CH2CH2CO2H (1:1 mole ratio)?

A) (CH3CH2CH2)2CCH2CH2CH2CH3

OHB)

CH3CH2CH2CCH2CH2CH2CH3

O

C)

CH3CH2CH2CH2COCH2CH2CH3

O

D) CH3CH2CH3 + CH3CH2CH2CH2CO2MgBr E)

CH3CH2COCCH2CH2CH2CH3

OO

Ans: D Topic: Synthetic Strategy

48.

Your task is to synthesize

CH3CH2CH2CCH3

C6H5

OH through a Grignard synthesis. Which pairs of compounds listed below would you choose as starting materials?

A)

CH3CC6H5CH3CH2CH2Br and

O

B)

CH3CH2CH2CH and C6H5Br

O

C)

C6H5CH

CH3CH2CHCH3

Brand

O

D) More than one of these E) None of these

Ans: A

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Topic: Synthetic Strategy

49. Which of the following synthetic procedures would be employed most effectively to transform ethanol into ethyl propyl ether?

A) Ethanol + HBr, then Mg/ether, then H3O+, then NaH, then CH3CH2Br B) Ethanol + HBr, then Mg/ether, then HCHO, then H3O+, then NaH, then CH3CH2Br C) Ethanol + CH3CH2CH2OH + H2SO4/140°C D) Ethanol + NaH, then HCHO, then H3O+, then HBr, then Mg/ether, then CH3CH2CH2BrE) Ethanol + H2SO4/180°C, then CH3CH2CH2Br

Ans: B Topic: Synthetic Strategy

50. Your task is to synthesize 2-phenyl-2-hexanol through a Grignard synthesis. Which pair(s) of compounds listed below would you choose as starting materials?

A)

CH3CC6H5CH3CH2CH2Br and

O

B) CH3CHCH2Br

CH3CC6H5

andO

CH3

C)

CH3CH2CH2CH2CCH3 and C6H5Br

O

D) Answers A) or B) E) Answers A) or C)

Ans: E Topic: Synthetic Strategy

51. How could the following synthesis be accomplished?

OH CH2CH

O

A)

(1) SOCl2, (2) Mg, ether, (3) CH3CH,

O

then H3O+ B) (1) SOCl2, (2) Li, ether, (3) (CH3CH2)2CuLi, (4) KMnO4, OH- C)

1) PBr3, (2) Mg, ether, (3) CH2 CH2,

O

then H3O+ (4) PCC,CH2Cl2 D) More than one of the above E) None of the above

Ans: C

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Topic: Synthetic Strategy, Redox

52. Select the correct reagent(s) for the following reaction:

CH3CCH2CH2CO2CH3

O

CH3CHCH2CH2CH2OH

OH

A) LiAlH4/ether; then H3O+ B) NaBH4; then H3O+ C) H2 with Pt/C D) A) and B) E) A), B) and C)

Ans: A Topic: Synthetic Strategy, Redox

53. Select the correct reagent(s) for the following reaction:

CH3CCH2CH2CO2CH3

O

CH3CHCH2CH2CO2CH3

OH

A) LiAlH4/ether; then H3O+ B) NaBH4; then H3O+ C) H2 with Pt/C D) B) and C) E) A), B) and C)

Ans: D Topic: Synthetic Strategy, Redox

54. Which reagent(s) would you use to convert CH3(CH2)6CO2H to CH3(CH2)6CH2OH? A) NaBH4/H2O B) LiAlH4/ether, then H3O+ C) PCC/CH2Cl2 D) Zn, H3O+ E) H2, Pt

Ans: B

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Topic: Synthetic Strategy

55.

Which method would give (CH3)2CC CH

OH

?

A) CH3CHCH3

OH

H2CrO4

aceticacid

HC CNa NH4+

B) CH3CCH3

O

CH3CH2Li H3O+ H2CrO4

acetoneC) CH3CC

O

2 CH3MgBr NH4+CH

D) More than one of the above E) None of the above

Ans: D Topic: Synthetic Strategy

56. Which synthesis of a Grignard reagent would fail to occur as written? A)

CH3OCH2CH2BrMg, ether

CH3OCH2CH2MgBrB)

CH3CH2CH2IMg, ether

CH3CH2CH2MgIC)

HO2CCH2CH2IMg, ether

HO2CCH2CH2MgID)

C6H5BrMg, ether

C6H5MgBrE) All of the above will succeed.

Ans: C Topic: Synthetic Strategy

57. Which combination of reagents is to be preferred for the synthesis of 2,4-dimethylhexane by the Corey-Posner, Whitesides-House procedure?

A) Lithium diisobutylcuprate + sec-butyl bromide B) Lithium dimethylcuprate + 2-bromo-4-methylhexane C) Lithium dimethylcuprate + 4-bromo-2-methylhexane D) Lithium diisopropylcuprate + 1-bromo-2-methylbutane E) Lithium di(2-methylbutyl)cuprate + isopropyl bromide

Ans: D

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Topic: Synthetic Strategy

58. Which of these reactions will not produce a 1° alcohol? A)

(CH3)2CHCH2CH2MgBr1. LiAlH4, Et2O

2. H3O+

B) CH2

O

CH2

(CH3)2CHCH2CH2MgBr

1.

2. H3O+

C)

C6H5CCH3

O 1. NaBH4

2. H3O+

D) CH3CH2CH2CH2Li

1. H2C=O

2. H3O+

E) CH3(CH2)5COOH

1. LiAlH4, Et2O

2. H3O+

Ans: C

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Topic: Synthetic Strategy, Stereochemistry

59. Which of the following would serve as a synthesis of racemic 2-methyl-1-phenyl-2-butanol?

CCH2CH3

CH2MgCl

CH2CCH3

I

II

III

CH3CH2CCH3

O 2. NH4+

CH3

OH

?

+1. Et2O

O+ CH3CH2MgBr

2. NH4+

1. Et2O

CH2CCH2CH3

O

+ CH3MgI2. NH4

+

1. Et2O

A) I B) II C) III D) All of the above E) None of the above

Ans: D

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Topic: Synthetic Strategy, Stereochemistry

60. Which of the following reactions would serve as a reasonable synthesis of the following racemic alcohol (2-phenyl-2-butanol)?

CH3CC6H5

C2H5

OH

A)

CH3CC6H5

O+ C2H5MgBr

2. NH4+

1. Et2O

B)

C2H5CC6H5

+ CH3MgBr2. NH4

+

1. Et2OO

C)

CH3CC2H5

+ C6H5MgBr2. NH4

+

1. Et2OO

D) Answers A) and B) only E) Answers A), B) and C)

Ans: E Topic: Synthetic Strategy, Stereochemistry

61. Which Grignard synthesis will produce an optically active product or product mixture?

A) MgBr

O+

B) OClMg+

C) O

O

MgI+

D) O

MgI

H CH3+

E)

O

H3C HMgBr+

Ans: E

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Topic: Synthetic Strategy, Stereochemistry

62. Which reaction leads to an optically active product? A)

O+ NaBH4

B) OClMg+

C) +

H CO2HH2, Pt

D)

+H OH

KMnO4

E) O

H3C CHO

O

LiAlH4 / Et2O (excess)+

Ans: C Topic: Acid/Base

63. Which of the following is the strongest acid? A) RMgX B) Mg(OH)X C) RH D) H2O

Ans: D Topic: Acid/Base

64. Which of the following is the strongest base? A) RMgX B) Mg(OH)X C) RH D) H2O

Ans: A Topic: Acid/Base

65. In which of the following series are the compounds arranged in order of decreasing basicity?

A) CH3CH2MgBr > NaNH2 > HC≡CNa > NaOH > CH3CH2ONa B) CH3CH2MgBr > NaNH2 > HC≡CNa > CH3CH2ONa > NaOH C) HC≡CNa > CH3CH2MgBr > NaNH2 > CH3CH2ONa > NaOH D) NaNH2 > CH3CH2MgBr > HC≡CNa > CH3CH2ONa > NaOH E) None of these

Ans: B

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Topic: Redox

66. Which reaction is an oxidation? A) RCHO ⎯⎯⎯⎯→ RCO2H B) RCH2OH ⎯⎯⎯⎯→ RCHO C) RCH2OH ⎯⎯⎯⎯→ RCO2H D) Two of these E) All of these

Ans: E Topic: Synthetic Strategy, Redox

67. Which of these compounds will not be reduced by LiAlH4? A) CH3CH2CH2CH=CH2 B)

CH3CH2CH2C

H

O

C)

CH3CH2CH2COH

O

D)

CH3CH2CH2COCH3

O

E)

CH3CH2CH2CCH3

O

Ans: A Topic: Synthetic Strategy, Redox

68. Which reagent(s) is/are capable of reducing the following ester to a primary alcohol ? O

O A) LiAlH4 / ether B) NaBH4 / H2O C) Na / C2H5OH D) H2 / Ni, atmospheric pressure E) All can be used successfully.

Ans: A

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Topic: Synthetic Strategy, Redox

69. Which reagent(s) is/are capable of reducing the following ester to an aldehyde ? O

O A) LiAlH4 / ether B) NaBH4 / H2O C) Na / C2H5OH D) H2 / Ni, atmospheric pressure E) None of the above can be used successfully.

Ans: E Topic: Redox

70. Which of these transformations cannot be classified as a reduction? A) RCH2Cl ⎯⎯⎯⎯→ RCH3 B) RCH=CH2 ⎯⎯⎯⎯→ RCH2CH3 C) RCOOH ⎯⎯⎯⎯→ RCH2OH D)

RCOR'

O

RCH2OH + R'OHE) All of these are reductions.

Ans: E Topic: Synthetic Strategy, Redox

71. Which of these compounds cannot be reduced by sodium borohydride? A)

(CH3)2CHC

H

O

B)

CH3CH2CCH3

O

C)

C6H5COH

O

D)

CH3(CH2)4COCH3

O

E) Neither C) nor D) can be reduced. Ans: E

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Topic: Redox, Reaction Mechanisms

72. In the reaction of carbonyl compounds with LiAlH4, the effective reducing species is: A) Li+ B) Al+3 C) AlH4

- D) AlH3 E) H-

Ans: E Topic: Redox, Reaction Mechanisms

73. The success in converting low molecular weight 1° alcohols to aldehydes by use of K2Cr2O7/H2SO4 as oxidant can be attributed to the fact that:

A) dichromate is a relatively weak oxidizing agent. B) the presence of H2SO4 limits the oxidation. C) the aldehyde can be separated, as formed, by distillation. D) aldehydes are not oxidized by the K2Cr2O7/H2SO4 mixture. E) hydrogen bonding occurs between the alcohol and the acid present.

Ans: C Topic: Redox, Reaction Mechanisms

74. Fundamentally, 2-methyl-2-pentanol does not undergo oxidation by H2CrO4 because: A) the intermediate chromate ester is not formed. B) the oxidant isn't in a sufficiently high oxidation state. C) the alcohol undergoes dehydration. D) the intermediate chromate ester cannot lose hydrogen. E) Actually, this oxidation does occur.

Ans: D

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Topic: Synthetic Strategy, Redox

75. Which of these reduction reactions is unsuccessful? A)

CH3CH2CH2COCH2CH2CH3

O

+ LiAlH4, etherB)

+ NaBH4, CH3OHC6H5CH2C O

H

C)

CH3(CH2)10COH + H2, Pt, high pressure

O

D)

C6H5CCH2CH2CH2CH3 + NaBH4, CH3CH2OH

O

E) All of these are successful reductions. Ans: C

Topic: Synthesis of Grignards and Other Organometallics

76. Grignard reagents react with oxirane (ethylene oxide) to form 1° alcohols but can be prepared in tetrahydrofuran solvent. Why is this difference in behavior observed?

A) Steric hindrance in the case of tetrahydrofuran precludes reaction with the Grignard. B) There is a better leaving group in the oxirane molecule. C) The oxirane ring is the more highly strained. D) It is easier to obtain tetrahydrofuran in anhydrous condition. E) Oxirane is a cyclic ether, while tetrahydrofuran is a hydrocarbon.

Ans: C Topic: Synthesis of Grignards and Other Organometallics

77. Which of these compounds cannot be used to prepare the corresponding Grignard reagent?

A) CH3OCH2CH2CH2Br B) (CH3)3CCl C) CH2=CHCH2Br D) (CH3)2NCH2CH2Br E)

O CCH2CH2I

H

Ans: E

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Topic: Synthesis of Grignards and Other Organometallics

78. Which of these compounds can be used to prepare the corresponding Grignard reagent? A) CH3CHOHCH2CH2CH2CH2Br B) (CH3)3CHCHBrCH2CH2CO2H C) BrCH=CHCH2CH2CH3 D) CH3NHCH2CH2Br E) None of the above can be used to prepare the corresponding Grignard reagent

Ans: C Topic: Reactivity of Grignards and Other Organometallics

79. Which of these is the least reactive type of organometallic compound? A) RK B) R2Hg C) RLi D) R2Zn E) R3Al

Ans: B Topic: Synthesis of Grignards and Other Organometallics

80. If the role of the solvent is to assist in the preparation and stabilization of the Grignard reagent by coordination with the magnesium, which of these solvents should be least effective?

CH3CH2OCH2CH3 O(CH3CH2)3N

CH3(CH2)4CH3 CH3OCH2CH2OCH3

I II III

IV VA) I B) II C) III D) IV E) V

Ans: D

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Topic: Synthesis of Grignards and Other Organometallics

81. Which of these is most likely to be a successful synthesis of an organometallic compound?

A) CH3CH2CH2MgBr + LiCl ⎯⎯⎯⎯→ CH3CH2CH2Li + MgBrCl B) 2 CH3CH2CH2CH2Li + ZnCl2 ⎯⎯⎯⎯→ (CH3CH2CH2CH2)2Zn + 2 LiCl C) 3 (CH3CH2)2Hg + 2 AlCl3 ⎯⎯⎯⎯→ 2 (CH3CH2)3Al + 3 HgCl2 D) (CH3CH2)3Al + 3 NaCl ⎯⎯⎯⎯→ 3 CH3CH2Na + AlCl3 E) (CH3)2Cu + MgBr2 ⎯⎯⎯⎯→ (CH3)2Mg + CuBr2

Ans: B SHORT ANSWER QUESTIONS Topic: General

82. Because the carbonyl carbon bears a partial positive charge, it is susceptible to ________________ attack. Ans: nucleophilic

Topic: General, Redox

83. A reaction which increases the hydrogen content or decreases the oxygen content of an organic molecule is called a(n) _____________. Ans: reduction

Topic: General, Redox

84. A reaction which increases the oxygen content or decreases the hydrogen content of an organic molecule is called a(n) _____________. Ans: oxidation

Topic: General, Redox

85. LAH is the abbreviation for the powerful reducing agent ______________. Ans: lithium aluminum hydride

Topic: General, Redox

86. A negatively charged hydrogen atom is called a ______________. Ans: hydride ion

Topic: General, Redox Reagents

87. A solution of CrO3 in aqueous acetone is called the _______________. Ans: Jones reagent

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Topic: Functional Group Tests

88. Primary and secondary alcohols can be distinguished from most other compounds (with the exception of aldehydes) because they will react rapidly with a solution of CrO3 in aqueous sulfuric acid, causing a color change from ______________ to _____________. Ans: orange; green

Topic: General

89. Compounds that contain carbon-metal bonds are known as _________________. Ans: organometallic compounds

Topic: General

90. Organomagnesium halides are known as _______________. Ans: Grignard reagents

Topic: Synthesis of Grignards and Other Organometallics

91. Why can we not prepare a Grignard reagent from a molecule such as 4-bromo-1-butanol? Ans: Because Grignard reagents are extremely strong bases and will react with the

alcohol's acidic proton. Topic: Reactions of Grignards and Other Organometallics

92. A Grignard reagent will produce a primary alcohol when reacted with ____________. Ans: Formaldehyde and ethylene oxide

Topic: Reactivity of Grignards and Other Organometallics

93. The reactivity of organometallic compounds increases with the _____________ of the carbon-metal bond. Ans: percent ionic character

Topic: Reactions of Grignards and Other Organometallics

94. A Grignard reagent will produce a secondary alcohol when reacted with ____________.Ans: Any aldehyde except formaldehyde

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Topic: Reactions of Grignards and Other Organometallics

95. Reaction of an alkyllithium with a ketone produces, after acid work-up, a _____________ alcohol. Ans: tertiary

Topic: Reactions of Grignards and Other Organometallics

96. Reaction of excess methyllithium with ethyl acetate (CH3CO2C2H5) produces, after acid work-up, ____________. Ans: t-butyl alcohol: (CH3)3COH

Topic: Reactions of Grignards and Other Organometallics

97. Reaction of excess ethyl magnesium bromide with ethyl benzoate (C6H5CO2C2H5) produces, after acid work-up, ____________. Ans:

3-phenyl-3-pentanol:

OH

Topic: Reactions of Grignards and Other Organometallics

98. Reaction of excess ethyl magnesium iodide with a ethyl acetate (CH3CO2C2H5) produces, after acid work-up, ____________ . Ans: 3-methyl-3-pentanol CH3CH2C(CH3)(OH)CH2CH3

Topic: Redox Reactions

99. In the reaction of carbonyl compounds with LiAlH4, the effective reducing species is: Ans: H− (hydride)

Topic: Redox Reactions

100. In the reaction of carbonyl compounds with NaBH4, the effective reducing species is: Ans: H− (hydride)

Topic: Grignard Reactions

101. NH4Cl is sometimes preferred instead of HCl or H2SO4 for “acid” work-up after Grignard reactions, particularly when the expected and desired product is a tertiary alcohol: why? Ans: NH4Cl provides mildly acidic conditions via partial hydrolysis of NH4Cl. Under

strongly acid conditions, a tertiary alcohol product can undergo facile dehydration to an alkene.

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Topic: Synthesis of Grignards and Other Organometallics

102. Diethyl ether, the most commonly used solvent for Grignard reactions, also acts as an ‘internal cooling agent’, preventing the overheating of the reaction mixture: what specific property of diethyl ether is exploited here and why is it important to prevent the overheating of the reaction mixture? Ans: Diethyl ether is very volatile (35-36oC): its low boiling point ensures that

reactions carried out in diethyl ether solvent cannot become overheated (the maximum temperature cannot exceed the b.p. of the solvent): this is important in Grignard reactions, because Grignard reagents decompose at higher temperatures. Thus, the decomposition of the newly formed Grignard reagent is minimized by use of this ‘internal cooling agent’.

Topic: General

102. When nucleophilic addition to a carbonyl group occurs, the carbon attacked undergoes this hybridization change: Ans: sp2 sp3

Topic: General, Redox

103. PCC and CrO3 are both Cr(VI) reagents. However, PCC/CH2Cl2 is useful in oxidizing primary alcohols to aldehydes, while the analogous reaction with CrO3/H2SO4 will typically produce carboxylic acids. Why? Ans: Both reagents first oxidize the alcohol to the corresponding aldehyde. Further

oxidation of aldehydes, to carboxylic acids, is facilitated in aqueous solutions, via formation of the intermediate aldehyde hydrates (CrO3/H2SO4). When the solvent is non-aqueous, such as CH2Cl2, these key intermediates cannot be formed, thereby preventing further oxidation of aldehydes (with PCC/CH2Cl2).

Topic: Multistep Reactions

104. What would be the major product, A, of the following reaction?

OCF3

S OO

OCH2CH3

Ai) NaBH4 ii) NaH, Et2Oiii)

Ans:

O

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Topic: Multistep Synthetic Strategy

105. Suggest a reasonable synthetic strategy for the synthesis of 3-methyl-3-hexanol from 3-hexanol. Ans: 3-hexanol- i) PCC; ii) CH3MgBr (or CH3Li); iii) NH4Cl

OHPCC CH2Cl2

Oi) CH3MgBr, Et2O ii) NH4Cl

OH

Topic: Multistep Synthetic Strategy

106. Suggest a reasonable synthetic strategy for the synthesis of 2-methyl-3-hexanol from 1-butanol. Ans: 1-butanol i) PCC; ii) (CH3)2CHMgBr (or (CH3)2CHLi); iii) NH4Cl (H3O+)

HOPCC CH2Cl2 O

i) (CH3)2CHMgBr, Et2O ii) NH4Cl

OH

Topic: Multistep Synthetic Strategy

107. Suggest a reasonable synthetic strategy for the synthesis of 4-heptanol from 1-pentene. Ans: 1-pentene i)MMPP; ii) CH3CH2MgBr (or CH3CH2Li); iii) NH4Cl (H3O+)

MMPP O i) CH3CH2MgBr, Et2O ii) NH4Cl

OH

Topic: Multistep Synthetic Strategy

108. Suggest a reasonable synthetic strategy for the synthesis of 3-ethyl-3-heptanol from pentanoic acid, CH3CH2CH2CH2CO2H. Ans: CH3CH2CH2CH2CO2H i)SOCl2; ii) 2 equivalents CH3CH2MgBr (or

CH3CH2Li); iii) NH4Cl (H3O+)

HO

OSOCl2

Cl

O OHi) CH3CH2MgBr (2 equivalents), Et2Oii) NH4Cl

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Topic: Multistep Reaction Sequence

109. Complete the following reaction sequence, giving structural details of all key intermediates. 1-hexene------------------ i) HBr ii) Li iii) (CH3CH2)2C=O iv) C2H5I Ans: Li

OLi

O

Li

C2H5I

BrHBr

O

Topic: Multistep Reaction Sequence

110. Complete the following reaction sequence, giving structural details of all key intermediates. 2-methyl-1-pentene------------------ i) BH3, THF ii) H2O2,NaOH iii) PCC, CH2Cl2 iv) CH3CH2C≡C:−Na+ v) NH4Cl Ans: i) BH3,THF

ii) H2O2, NaOHHO

O

PCC,CH2Cl2

:− Na+

HO

i)

ii) NH4Cl

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Topic: Multistep Reaction Sequence

111. Complete the following reaction sequence, giving structural details of all key intermediates. 4-methyl-1-hexene------------------ i) BH3, THF ii) H2O2,NaOH iii) SOCl2 iv) Mg, Et2O iv) ethylene oxide v) NH4Cl Ans:

O

ClMgMgEt2O

HO

HO

Cl

i) BH3,THFii) H2O2, NaOH

i)

ii) NH4Cl

SOCl2

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Topic: Multistep Reaction Sequence

112. Complete the following reaction sequence, giving structural details of all key intermediates. Bromocyclohexane------------------ i) Li ii) CuI iii) 4-methyl-1-bromohexane Ans:

CuLiLi CuIBr Li

Br

2

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MULTIPLE CHOICE QUESTIONS Topic: Nomenclature

1.

What is an IUPAC name for A) 2,3-methylhept-2-en-4-yne B) 1,1,3-trimethylhex-3-yn-1-ene C) 1,1,3-trimethyl-3-hexyn-1-ene D) 2,3-dimethyl-2-hepten-4-yne E) 5,6-dimethyl-5-hepten-3-yne

Ans: D Topic: Nomenclature

2. What is an IUPAC name for this triene?

HH

CH3CH2H H

H

H

CH3

A) (2E,4Z,6E)–2,4,6–Nonatriene B) (2Z,4E,6Z)–2,4,6–Nonatriene C) (2E,4Z,6Z)–2,4,6–Nonatriene D) (3Z,5Z,7E)–3,5,7–Nonatriene E) (3Z,5E,7E)–3,5,7–Nonatriene

Ans: C Topic: Nomenclature

3. What is an IUPAC name for this triene?

A) (2E,4Z,6E)–3,4,7,8–tetramethyl-2,4,6–Nonatriene B) (2Z,4E,6E)–3,4,7,8–tetramethyl-2,4,6–Nonatriene C) (2E,4Z,6E)–2,3,6,7–tetramethyl-3,5,7–Nonatriene D) (2E,4Z,6E)– 2,3,6,7–tetramethyl-3,5,7–Nonatriene E) (2E,4E,6E)–3,4,7,8–tetramethyl-2,4,6–Nonatriene

Ans: E

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4.

A correct IUPAC name of the compound below is:

Br

A) 1-Bromo-1-methyl-2,5-cyclohexadiene B) 3-Bromo-3-methyl-1,4-cyclohexadiene C) 6-Bromo-6-methyl-1,4-cyclohexadiene D) 2-Bromo-2-methyl-1,3-cyclohexadiene E) None of these

Ans: B Topic: Stability (Alkenes, Cations, Radicals)

5. Which of the following dienes would you expect to be the most stable? A) CH3CH=CHCH=CHCH3 B) CH3CH=CHCH2CH=CH2 C) CH2=CHCH2CH2CH=CH2 D) CH2=CHCH(CH3)CH=CH2 E) CH3CH=C=CHCH2CH3

Ans: A Topic: Stability (Alkenes, Cations, Radicals)

6. Which of the following dienes would you expect to be the most stable? A) CH3CH2CH=CHCH2CH=CHCH3 B) CH3CH=CHCH=CHCH2CH3 C) CH2=CHCH2CH2CH2CH=CH2 D) CH2=CHCH=CHCH2CH2CH3 E) CH3CH2CH=C=CHCH2CH3

Ans: B

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Topic: Stability (Alkenes, Cations, Radicals)

7. Which of the following compounds would be the most stable?

I II III IVA) I B) II C) III D) IV E) They are all of equal stability.

Ans: A Topic: Stability (Alkenes, Cations, Radicals)

8. Considering both configurational and conformational factors, select the most stable form of 2,4-hexadiene.

H

CH3 H

H

H

CH3

CH3

H H

H

H

CH3 HCH3

CH3

H

HH

CH3H

H

CH3CH3H

CH3

H

I II III IV V

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Stability (Alkenes, Cations, Radicals)

9. Which alkene would you expect to be most stable? A) CH2=CHCH2CH2CH=CH2 B)

C CH

CH3H

CHCH2CH2

C) C C

CH3 CH2CH

H H

CH2

D)

C CC

HH

CH3 CH

CH3

H

E) C C

CH3

H C

H

CH

H

CH3

Ans: E Topic: Stability (Alkenes, Cations, Radicals) 10. Which diene would be least stable?

I II III IV V

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Stability (Alkenes, Cations, Radicals)

11. Arrange these hexadienes in order of expected decreasing stability.

I II

IV V

III

A) V > II > I > III > IV B) III > IV > II > I > V C) IV > III > II > V > I D) IV > III > I > II > V E) I > II > IV > III > V

Ans: D Topic: Stability (Alkenes, Cations, Radicals)

12. Which carbocation would be most stable? A)

B)

C)

D)

E)

Ans: C

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Topic: Stability (Alkenes, Cations, Radicals)

13. Which carbocation would be most stable?

I II III IV V

CH2 CH3 CH3 CH3 CH3

A) I B) II C) III D) IV E) V

Ans: C Topic: Stability (Alkenes, Cations, Radicals)

14. Which free radical would be most stable? A)

CH3CC CH2

CH3

B)

CCH2CH2

CH3

CH2

C)

CH3CCH2CH3

CH3

D)

CH2CHC CH2

CH3

E)

CH3CHCHCH3

CH3

Ans: A

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Topic: Stability (Alkenes, Cations, Radicals)

15.

Which hydrogen atom(s) of

CH CHCHCH3 CH

CH3

CH CH3

I II III IV

V

is/are most susceptible to abstraction by free radicals?

A) I B) II C) III D) IV E) V

Ans: D Topic: Heat of Hydrogenation

16. Which alkene would you expect to have the smallest heat of hydrogenation? A) CH2=CHCH2CH2CH=CH2 B)

C CH

CH3H

CHCH2CH2

C) C C

CH3 CH2CH

H H

CH2

D)

C CC

HH

CH3 CH

CH3

H

E) C C

CH3

H C

H

CH

H

CH3

Ans: E

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Topic: Bond Lengths

17. Which compound would have the shortest carbon-carbon single bond? A) CH3–CH3 B) CH2=CH–CH3 C) HC≡C–C≡CH D) CH2=CH–C≡CH E) CH2=CH–CH=CH2

Ans: C Topic: Bond Lengths

18. Which compound would have the shortest carbon-carbon single bond?

A) CH≡C–CH=CH–CH2–CH3 B) CH2=CH–CH=CH–CH3 C) HC≡C–CH2–C≡C–CH3 D) CH2=CH–C≡C–CH2–CH3 E) CH3–C≡C–C≡C–CH3

Ans: E Topic: Bond Lengths

19. Which carbon-carbon bond in the following compound would you expect to be shortest?C C CHH CH2 CH3CH

I II III IV VA) I B) II C) III D) IV E) V

Ans: A

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Topic: Bond Lengths

20. Which carbon-carbon bond in the following compound would you expect to be longest? C C CHH CH2 CH3CH

I II III IV VA) I B) II C) III D) IV E) V

Ans: E Topic:Alkene Classification

21. Select the structure of the conjugated diene.

I II III IV VA) I B) II C) III D) IV E) V

Ans: B

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Topic:Alkene Classification

22.

Select the structure(s) of the conjugated diene(s).

I II

IV V

III

A) I and II B) II and III C) III and IV D) I, II and V E) V

Ans: B Topic: Alkene Classification

23. Which of the following dienes is a cumulated diene? A) CH2=CHCH2CH2CH=CH2 B) CH2=CHCH=CHCH2CH3 C) CH3CH=C=CHCH2CH3 D) CH3CH=CHCH=CHCH3 E) CH3CH=CHCH2CH=CH2

Ans: C Topic: Alkene Classification

24. Which of the following dienes is a cumulated diene? A) CH2=CHCH2CH2CH2CH=CH2 B) CH2=CHCH=CHCH2CH2CH3 C) CH3CH=C=CHCH2CH2CH3 D) CH3CH=CHCH=CHCH2CH3 E) CH3CH2CH=CHCH2CH=CH2

Ans: C

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Topic: Molecular Orbitals

25. The allyl radical has how many bonding π molecular orbitals? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: A Topic: Molecular Orbitals

26. The allyl cation has how many electrons in bonding π molecular orbitals? A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B Topic: Molecular Orbitals

27. 1,3-Pentadiene has how many bonding π molecular orbitals? A) 1 B) 2 C) 3 D) 4 E) 0

Ans: B

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Topic: Heat of Hydrogenation

28. Estimate the stabilization energy for 1,3-butadiene using the heats of hydrogenation in Table 1. Table 1. Heats of Hydrogenation for Selected Compounds Compound Moles H2 ΔH(kJ mol-1) 1-Butene 1 -127 1-Pentene 1 -126 1,3-Butadiene 2 -239 1,3-Pentadiene 2 -226

A) 13 kJ mol-1 B) 15 kJ mol-1 C) 28 kJ mol-1 D) 239 kJ mol-1 E) 112 kJ mol-1

Ans: B Topic: Resonance

29. Which is not an example of resonance? I

III

IV

II CH2

CH2

CH2=CH−CH2

CH2=CH−CH−CH2CCl3

CH2

CH3

CH2−CH=CH2

CH2−CH=CH−CH2CCl3

. .

+

++

. .

A) I B) II C) III D) IV E) None of these are examples of resonance

Ans: C

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Topic: Resonance

30. Which is not a proper resonance structure for 1,3-butadiene? A) CH2=CH–CH=CH2 B)

CH CH2CHCH2

C) CH CH2CHCH2

D) CHCH2 CH CH2

E) All are correct Ans: B

Topic: Resonance

31. Which pair does not represent a pair of resonance structures?

I

II

III

IV

H

H

HH

H

H

H

HH

H

H

H

HH

H

H

H

HH

H

CH2 CH2

CH2 CH3

and

and

and

and

A) I B) II C) III D) IV E) All of these represent pairs of resonance structures.

Ans: D

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Topic: Reaction Mechanisms and Control

32. A thermodynamically-controlled reaction will yield predominantly: A) the more/most stable product. B) the product whose formation requires the smallest free energy of activation. C) the product that can be formed in the fewest steps. D) the product that is formed at the fastest rate. E) the product which possesses the greatest potential energy.

Ans: A Topic: Reaction Mechanisms and Control

33. A reaction under kinetic (or rate) control will yield predominantly: A) the most stable product. B) the product that can be formed in the fewest steps. C) the product whose formation requires the smallest free energy of activation. D) the product with the greatest potential energy. E) the product with the least potential energy.

Ans: C Topic: Reaction Mechanisms and Control

34. The accompanying diagram, which describes the fate of the intermediate in a reversible reaction, implies that:

A

BE

reaction coordinate A) the less stable product forms more rapidly. B) the more stable product forms more rapidly. C) product B will predominate at equilibrium. D) the intermediate has a short lifetime. E) No conclusions can be drawn as to either reaction rate or product stability.

Ans: B

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Topic: Reaction Mechanisms and Control

35. The accompanying diagram implies that:

A

BE

reaction coordinate A) The formation of B from A would be favored at high temperature. B) The more stable product forms more rapidly from the intermediate species. C) The formation of the intermediate from A is the rate-limiting step in the transformation

of A into B D) The formation of B from A is not a concerted reaction. E) All of the above statements are true

Ans: E Topic: Diels-Alder Reaction

36. Which is an untrue statement concerning the Diels-Alder reaction? A) The reaction is a syn addition. B) The diene must be in the s-cis conformation to react. C) Most Diels-Alder reactions are reversible. D) Generally, the adduct formed most rapidly is the exo product. E) Depending on the nature of the dienophile, both electron-releasing and electron-

withdrawing groups in the diene can favor adduct formation. Ans: D

Topic: Diels-Alder Reaction

37. does not undergo the Diels-Alder reaction because:

A) ring systems cannot function as the diene component. B) it cannot adopt the s-cis conformation. C) it lacks electron-withdrawing groups. D) it lacks strong electron-releasing groups. E) the two double bonds are further apart than in a non-cyclic conjugated system.

Ans: B

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Topic: Diels-Alder Reaction

38. does not undergo the Diels-Alder reaction because:

A) ring systems cannot function as the diene component. B) it cannot adopt the s-cis conformation. C) it lacks electron-withdrawing groups. D) it lacks strong electron-releasing groups. E) the two double bonds are further apart than in a non-cyclic conjugated system.

Ans: B Topic: Diels-Alder Reaction

39. Which of these dienes is the most reactive in the Diels-Alder reaction? A) 1,3-Butadiene B) 1,4-Pentadiene C) Cyclopentadiene D) 1,2-Butadiene E) 1,4-Cyclohexadiene

Ans: C Topic: Diels-Alder Reaction

40. Which of these dienes can undergo the Diels-Alder reaction? A) 1,3-Pentadiene B) 1,4-Pentadiene C) 1,2-Butadiene D) 1,4-Cyclohexadiene E) All of the above can undergo the Diels-Alder reaction

Ans: A Topic: Diels-Alder Reaction

41. Which of these dienes can undergo the Diels-Alder reaction? A) 1,2-Heptadiene B) 1,3-Heptadiene C) 1,4-Heptadiene D) 1,5-Heptadiene E) 1,6-Heptadiene

Ans: B

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Topic: Diels-Alder Reaction

42. Which diene and dienophile would you choose to synthesize the following compound?

H

COCH3

O

and CH2 CH2 and

and and

HC CCOCH3

O

CH2 CHCOCH3

O

CH2 CHCOCH3

O

I II

III IVA) I B) II C) III D) IV E) None of these

Ans: C Topic: Diels-Alder Reaction

43. Which diene would be least reactive toward Diels-Alder addition of maleic anhydride?

CH CH2CHCH2 C CH2CHCH2

CH3

C CH2CCH2

CH3CH3

I II III

IV VA) I B) II C) III D) IV E) V

Ans: E

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Topic: Diels-Alder Reaction

44. What would be the product of the following reaction?

CHCCH3CH2

I II III IV

O+

heat

CCH

CH3

CH2C C

O

CH3

O

CH3

C

O

CH3

A) I B) II C) III D) IV E) All of these

Ans: C

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Topic: Diels-Alder Reaction

45. How would you synthesize:

I

II

III

IV

OH

COCH3

O

1,3-Cyclohexadiene + CHCOCH3,CH2

O

then RCOOH

O

1,3-Cyclohexadiene + CHCOCH3,CH2

O

thenRCOOH,

O

COCH3

O

CH2

O

CH2+

1,4-Cyclohexadiene + CHCOCH3,CH2

O

thenCH2

O

CH2

COCH3

O

OCH2CH2+V

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Diels-Alder Reaction

46. Which of the following would afford a synthesis of the following compound?

CHO

CH3CH CHCH32 +CHO

CH3CH CH2

CHO

CH2 CHCHO+

CH2 CHCHO+

+

I

II

III

IV

A) I B) II C) III D) IV E) None of these

Ans: D

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Topic: Diels-Alder Reaction

47. Which diene would you expect to react most rapidly with maleic anhydride?

CH3

CH3

CH3

CH3

CH3C

CH3C

O

OI II III IV V

A) I B) II C) III D) IV E) V

Ans: D Topic: Diels-Alder Reaction

48. Which of these conjugated dienes can undergo a Diels-Alder reaction?

CH2 CH2

C(CH3)3CH2

(CH3)3C

I II III IV VA) I B) II C) III D) IV E) V

Ans: C

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Topic: Diels-Alder Reaction

49. Which of these conjugated dienes can undergo a Diels-Alder reaction?

I II III

IV V

A) I and V B) I, II and V C) III D) IV E) III and IV

Ans: D

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Topic: Diels-Alder Reaction

50. Which diene and dienophile would you choose to synthesize the following compound?

OHCOCH3

O

COCH3

O

O

O O

and O2and

CH2 CH COCH3

O

CH2 CH COCH3

Oand and

HC C COCH3

O

I II

III IVA) I B) II C) III D) IV E) None of these

Ans: C

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Topic: Diels-Alder Reaction

51. Which diene and dienophile would you choose to synthesize the following compound?

CHO

CHO

I

IV

CHOH

CHOH

CHO

CHO

OHC

CHO

CHO

CHO

II III

V VIA) I and VI B) II and V C) III and IV D) IV and V E) I and III

Ans: E

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Topic: Diels-Alder Reaction

52. Which compounds could be used in a Diels-Alder synthesis of

CH2 CHCO2CH3 HC CCO2CH3

CH3

CH3

CO2CH3

?

CH3

CH3 CH3

CH3

I II III IVA) I and III B) I and IV C) II and III D) II and IV

Ans: C Topic: Diels-Alder Reaction

53. Which is the major product of the following reaction?

C

C

H C

CH

OH

O

O

OH

CO2H

H

H

CO2HCO2H

CO2H

H

HH

CO2H

CO2H

HH

H

CO2H

CO2H

I II III IV

+ ?

A) I B) II C) III D) IV E) None of these

Ans: D

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Topic: Diels-Alder Reaction

54. Which is the major product of the following reaction?

CHO

HH

CHO

III III V

H

HCHO

CHO

CHO

CHOH

H

H

CHOCHO

H

IV

H

HCHO

CHO

CHO

CHO

+ ?

A) I B) II C) III D) IV E) V

Ans: A Topic: Diels-Alder Reaction

55. Which is the major product of the following reaction?

CHO

CHO

III III V

H

HCHO

CHO

CHO

CHOH

H

H

CHOCHO

H

IV

CHO

CHO

CHOOHC+ ?

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Diels-Alder Reaction

56. Which is the major product of the following reaction?

CHO

III III V

H

HCHO

CHO

CHO

CHOH

H CHO

IV

CHO

CHO+ ?

A) I B) II C) III D) IV E) V

Ans: III

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Topic: Diels-Alder Reaction

57. Which diene and dienophile would you choose to synthesize the following compound?

COCH3

O

O

O

and O2and

CH2 CH COCH3

O

CH2 CH COCH3

Oand and

HC C COCH3

O

I II

III IV

OCOCH3

O

A) I B) II C) III D) IV E) None of these

Ans: B Topic: Diels-Alder Reaction

58.

Which of the following can undergo the Diels Alder reaction?

I

IV

II

V

III

A) I and II B) II and III C) III and IV D) I, II and V E) V

Ans: C

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Topic: Diels-Alder Reaction

59. From the standpoint of reactivity, which is the poorest choice of dienophile to react with 2,3-dimethyl-1,3-butadiene in a Diels-Alder reaction?

O

I II

O O

III

H3CO

OCH3O

O

IV

OCH3H3CO

O

OV

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Diels-Alder Reaction

60. What is the product of the following reaction?

CH CH2+

CH3C C C CCH3

OO?

COCH3

COCH3COCH3

COCH3

COCH3

COCH3

COCH3

COCH3 COCH3

COCH3

I II III

IV VA) I B) II C) III D) IV E) V

Ans: A

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Topic: Diels-Alder Reaction

61. Which would be the best synthesis of the following compound?

CO2CH3CO2CH3

CO2CH3

CO2CH3

+CO2CH3

CO2CH3

+CO2CH3

+CH3O2C

CO2CH3

CO2CH3

+ + 2 HCO2CH3

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Diels-Alder Reaction

62. Which reaction would produce the following compound?

H

H

CO2CH3

CO2CH3

+CO2CH3

CO2CH3

+CO2CH3

+

CH3O2C

I II

III IV

H

H

H

H

CO2CH3

CO2CH3

H

H

+CO2CH3

CO2CH3

H

H

A) I B) II C) III D) IV E) None of the above

Ans: D

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Topic: Diels-Alder Reaction

63. Which of the following pairs of compounds could be used as the basis for a Diels-Alder synthesis of the compound shown below?

CO2CH3

CH3CH CHCH32 +CO2CH3

CH3CH CH2

CO2CH3

CH2 CHCO2CH3+

CH2 CHCO2CH3+

+

I

II

III

IV

A) I B) II C) III D) IV E) More than one of the above

Ans: D

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Topic: Multi-step Synthesis

64. How could the following synthesis be carried out?

CH2CH3

A) (1) Br2/CCl4; (2) CH3CH2MgCl, ether; (3) CH3ONa/CH3OH B) (1) HBr, 80°C; (2) (CH3CH2)2CuLi, ether C) (1) HBr, 80°C; (2) Mg, ether; (3) CH3CH2OH, then H3O+ D) More than one of the above E) All of the above

Ans: B Topic: Multi-step Reaction Sequence

65. How could the following synthesis be carried out?

A) (1) Br2/CCl4; (2) CH3MgCl, ether; (3) CH3ONa/CH3OH B) (1) HBr (1 eq); (2) (CH3)2CuLi, ether C) (1) HBr (1eq); (2) Li, ether; (3) CuI; (4) CH3Br D) More than one of the above E) All of the above

Ans: C Topic: Allylic Substitution

66. What product(s) would you expect from the following substitution reaction of 14C-labeled propene?

14CH2 CH CH3

Cl2

500 oC?

A) 14CH2=CH–CH2Cl alone B) 14CH2=CH–CH2Cl and CH2=CH–14CH2Cl, in equal amounts C) CH2=CH–14CH2Cl alone D) more 14CH2=CHCH2Cl, but a little CH2=CH–14CH2Cl E) more CH2=CH–14CH2Cl, but a little 14CH2=CHCH2Cl

Ans: B

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Topic: Allylic Substitution

67. What product(s) would you expect from the following substitution reaction?

ClCl Cl Cl

I II III IV

* * * *

Cl2500oC

* ?

A) I B) II C) III D) IV E) More than one of the above

Ans: E Topic: Synthesis of Allylic Halides

68. Which of the following could be used to synthesize 3-bromopropene? A)

CH3CH CH2 + Br225 oC

CCl4B)

CH3CH CH2 + N-bromosuccinimideCCl4

ROOR

C) CH2=CHCH2OH + PBr3 ⎯⎯⎯⎯→ D) More than one of these E) None of these

Ans: D Topic: Synthesis of Allylic Halides

69. Which of the following could be used to synthesize 3-bromocyclopentene? A) Cyclopentene + Br2, CCl4 , 25o B) Cyclopentene + NBS, CCl4 (ROOR) C) 3-Cyclopentenol + PBr3 D) Both A) and B) E) Both B) and C)

Ans: E

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Topic: Synthesis of Allylic Halides

70. Treatment of 2-butene (cis or trans) with N-bromosuccinimide in CCl4 would yield mainly:

A) CH3CHBrCHBrCH3 alone B) CH3CH=CBrCH3 alone C) CH3CH=CHCH2Br alone D) CH2BrCH2CH=CH2 and CH3CH=CHCH2Br E) CH3CHBrCH=CH2 and CH3CH=CHCH2Br

Ans: E Topic: Synthesis of Allylic Halides

71. Treatment of 4-methylcyclohexene with N-bromosuccinimide in CCl4 would yield mainly:

Br

Br Br

Br

I II III IV A) I B) II C) III D) IV E) All of the above

Ans: E

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Topic: Multistep Reactions

72. Which would be the best synthesis?

CH2 CHCH3

?CH2CHCH2Cl

Br BrA)

PropeneBr2, CCl4 Cl2, hν

B) Propene

Cl2, 400 oC Br2, CCl4

C) Br2, hνPropene

HCl

D) Propene

Cl2, CCl4NBS, CCl4

E) Propene

Cl2, CCl4 NBS, CCl4

Ans: B Topic: Ozonolysis of Polyenes

73. Which is the diene that yields on ozonolysis (O3, followed by Zn/HOAc) an equimolar

mixture of CH2O, CH3CHO, and

CHO

CH2

CHO

CH2 CH

CH3

CH CH CH2 CH3

CH2 CH CH2 CH CH CH3 CH2 CH CH2 CH2 CH CH2

I II III

IV V

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Allylic Halogenation

74. What is (are) the product(s) of the following reaction?

Cl ClCl

I II III

Cl2400oC

?

A) I B) II C) III D) a mixture of I and II E) a mixture of II and III

Ans: E Topic: Allylic Halogenation

75. Which set of conditions does not result in allylic halogenation of an alkene? A) Cl2 at 400°C B) Cl2 in CCl4 at 25°C C) Cl2, ROOR,hν D) Br2 at low concentration in CCl4 E) N-Bromosuccinimide in CCl4, ROOR

Ans: B Topic: Allylic Halogenation

76.

Which carbon of

CH3 CH CH2 CH CH2

CH3

V IV III II I is predicted to be the major site of substitution when this alkene reacts with chlorine at 400°C?

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Allylic Halogenation

77. Which carbon is predicted to be the major site of substitution when this alkene reacts with NBS?

II

V

IIII IV

A) I B) II C) III D) IV E) V

Ans: B Topic: Diene Synthesis

78. Which of these is not a useful method for the synthesis of 1,3-pentadiene? A) 1,4-pentanediol + H2SO4 at 180oC B) 2,4-dibromopentane + (CH3)3COK , (CH3)3COH at 75oC C) 2,4-pentanediol + H2SO4 at 180oC D) HC≡CCH=CHCH3 + H2, Ni2B (P-2) E) 1,4-dibromopentane + CH3CH2ONa , CH3CH2OH at 75oC

Ans: B

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Topic: Conjugate Addition Reactions

79. Ignoring stereochemistry, the 1:1 reaction of bromine with 1,3-cyclohexadiene at 25°C in the dark and in the absence of peroxide forms which of these?

Br Br Br

Br

Br

Br Br

I II III IVA) I B) II C) III D) IV E) Both I and II

Ans: E Topic: Conjugate Addition Reactions

80. Which is the only compound which can be completely ruled out as a product of the reaction of 1,3-butadiene with HCl?

A) (S)-3-chloro-1-butene B) (R)-3-chloro-1-butene C) (E)-1-chloro-2-butene D) (Z)-1-chloro-2-butene E) (Z)-2-chloro-2-butene

Ans: E Topic: Diene Synthesis

81. Hot alumina can be used as an effective dehydrating agent: when 3-methyl-2,3-pentanediol vapor is passed over hot alumina (Al2O3), the chief product to be expected is which of these?

A) 2-Ethyl-1,3-butadiene B) 3-Methyl-1,3-pentadiene C) 3-Methyl-1,2-pentadiene D) 3-Methyl-2,3-pentadiene E) 3-Methyl-1,4-pentadiene

Ans: B

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Topic: Allylic Halogenation

82. An unsaturated product results from the reaction of cyclohexene with which of these? A) Br2/CCl4 at 25°C B) NBS/CCl4, ROOR C) HCl, ROOR D) HCl, no peroxides E) More than one of these

Ans: B Topic: Conjugate Addition Reactions

83. Which of the following dienes might react with bromine in CCl4 to yield 2,5-dibromo-3-hexene?

A) CH2=CHCH2CH2CH=CH2 B) CH2=CHCH=CHCH2CH3 C) CH3CH=C=CHCH2CH3 D) CH3CH=CHCH=CHCH3 E) CH3CH=CHCH2CH=CH2

Ans: D Allylic Halogenation

84. What product(s) would you expect from the following substitution reaction of 14C-labeled propene?

14CH2 CH CH3

N-bromosuccinimide

ROOR, CCl4?

A) 14CH2=CH–CH2Br alone B) 14CH2=CH–CH2Br and CH2=CH–14CH2Br in equal amounts C) CH2=CH–14CH2Br alone D) More 14CH2=CHCH2Br but a little CH2=CH–14CH2Br E) More CH2=CH14CH2Br but a little 14CH2=CHCH2Br

Ans: B

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Allylic Halogenation

85. Treatment of 2-butene (cis or trans) with Cl2 at 400°C would yield mainly: A) CH2ClCHClCH2CH3 B) CH3CHClCH2CH3 C) CH3CH=CClCH3 D) CH3CH=CHCH2Cl and CH3CHClCH=CH2 E) CH3CHClCHClCH3

Ans: D Topic: Conjugate Addition Reactions

86. Indicate which products would be obtained from the chlorination of 1,5-hexadiene at high temperature (500°C), using a 1:1 mole ratio of the reactants.

ClCH2CHCH2CH2CH CH2

V

Cl

CHCH CHCH2ClClCH2CH

CHCH2CH CH2ClCH2CH

CHCH2CHCH CH2CH2

Cl

ClCH2CHCH2CH2CHCH2Cl

Cl Cl

I II

III

IVA) I and II B) II and III C) III and IV D) IV and V E) V and I

Ans: C

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Topic: 1,2 Reactions of Conjugated Dienes

87. Which reagent would convert 1,3-pentadiene into 3-penten-2-ol?

A) KMnO4/-OH B) OsO4 C) H2O2, then H3O+ D) Cl2/H2O E) H3O+

Ans: E Topic: 1,2 Reactions of Conjugated Dienes

88. Which reagent would convert 1,3-octadiene into 3-octen-2-ol? A) KMnO4/-OH B) OsO4 C) H2O2, then H3O+ D) Cl2/H2O E) H3O+

Ans: E Topic: UV-Vis Spectroscopy

89. Which compound would have an UV absorption band at longest wavelength?

CH CHCH3

CHCH CH CHCH3

CH2CH CH2 CH CHCH3

CH2

I II III

IV VA) I B) II C) III D) IV E) V

Ans: B

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Topic: UV-Vis Spectroscopy

90. Select the most energetically favorable UV transition for 1,3-butadiene. A) n ⎯⎯⎯→ σ* B) n ⎯⎯⎯→ π* C) π2 ⎯⎯⎯→ π3* D) σ ⎯⎯⎯→ σ* E) π1 ⎯⎯⎯→ π4*

Ans: C Topic: UV-Vis Spectroscopy

91. Which compound would have an UV absorption band at longest wavelength?

CH CH CH

CHCH2CH2CH

CHCH CH2 CHCH CH2 CHCH CH2

CH2 CHCH CH2

I II III

IV VA) I B) II C) III D) IV E) V

Ans: A Topic: UV-Vis Spectroscopy

92. Which of these symbols is used in connection with the intensity of absorption in the UV-visible region?

A) ∝ B) ν C) ε D) λ E) θ

Ans: C

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Topic: Allylic Halogenation

93. Which of the following compounds is not formed as a result of a chain-termination step in the free radical chlorination of propene?

A) CH2=CHCH2Cl B) Cl2 C) CH2=CHCH2CH2CH=CH2 D) HCl E) All can be formed in chain-termination steps.

Ans: D SHORT ANSWER QUESTIONS Topic: General

94. Systems that have a p orbital on an atom adjacent to a double bond are called ______________ systems. Ans: conjugated unsaturated

Topic: General

95. The hydrogen atom on a saturated (sp3) carbon adjacent to a double bond is called an ______________ hydrogen. Ans: allylic

Topic: General 96. The hydrogen atom on a carbon that is part of a double bond is called a ___________

hydrogen. Ans: vinyl or vinylic

Topic: General

97. Allylic radicals are ___________ stable than tertiary radicals. Ans: more

Topic: General 98. Vinyl cations are _____________ stable than tertiary cations.

Ans: less

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Topic: General

99. There are three types of polyenes (molecules containing two or more double bonds). They are: _________________. Ans: conjugated, cumulated, isolated

Topic: General

100. Polyenes in which single and double bonds alternate along the carbon chain are called ___________. Ans: conjugated

Topic: General

101. UV-vis spectroscopy can be used to indicate whether _________________ is present. Ans: conjugation

Topic: General

102. When the product distribution for a particular reaction reflects the relative stabilities of the products, the reaction is said to be under ______________ control. Ans: thermodynamic

Topic: General

103. When the product distribution for a particular reaction reflects the relative rate at which the products are formed, the reaction is said to be under _______________ control. Ans: kinetic

Topic: General

104. The Diels-Alder reaction is a cycloaddition between a conjugated ________ and a ___________. Ans: diene; dienophile

Topic: General

105. A thermodynamically-controlled reaction will yield predominantly:___________. Ans: the more/most stable product.

Topic: General

106. A reaction under kinetic (or rate) control will yield predominantly:___________. Ans: the product whose formation requires the smallest free energy of activation.

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Topic: General

107. Stereochemically speaking, the Diels-Alder reaction is ___________ and occurs with ___________ of the dienophile stereochemistry. Ans: stereospecific; retention

Topic: General

108. Conjugated dienes routinely undergo 1,2 and 1,4 addition reactions with a variety of electrophilic reagents; this suggests that ___________ are likely intermediates during these reactions. Ans: allylic carbocations

Topic: Diels –Alder Reactions

109. During Diels Alder reactions, when two stereoisomer products, exo and endo, are possible, the ___________ product is typically obtained as the major product. Ans: endo

Topic: Nomenclature

110. Draw the structural formula for (2E,4Z,6E)–3,4,7,8–tetramethyl-2,4,6–nonatriene, clearly indicating stereochemical details. Ans:

Topic: Nomenclature

111. Draw the structural formula for (2Z,4Z,6Z)-3,4,8-trimethyl-2,4,6-nonatriene,clearly indicating stereochemical details. Ans:

Topic: Nomenclature

112. Draw the structural formula for (R)-5-bromo-2,5-dimethyl-1,3-cyclopentadiene, clearly indicating stereochemical details. Ans: CH3

Br

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Topic: Multistep Reactions

113. Complete the following sequence of reactions, giving structural details of all key intermediates.

O

O+

heatA B

H2Ni

Ans: O

O+ heat

O

O

O

O

+

H2, Ni

O

O

O

O

+

O

O

O

O

+

+ +

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Topic: Multistep Reactions

114. Complete the following sequence of reactions, giving structural details of all key intermediates.

i) NBSii) (CH3)3COK, (CH3)3COH, heatiii) trans CH3CH=CHCHO

?

Ans:

O

NBSBr

O O

(CH3)3COK,(CH3)3COH, heat

+

Topic: Multistep Reactions

115. Complete the following sequence of reactions, giving structural details of all key intermediates.

i) cis-CH3CH=CHCHO

ii) CH3CH2MgBr

iii) H3O+

?

Ans: CHO CH3

O

H

HCH3

HO

H

Hi) CH3CH2MgBr

ii) H3O+

Topic: Diels Alder Reaction

116. What reagents would be needed to synthesize the following substance via the Diels-Alder reaction? Give stereochemical details, as relevant.

O

O

O Ans:

O

O

O

+

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MULTIPLE CHOICE QUESTIONS Topic: Bonding and Resonance

1. Which of the following is NOT true of benzene? A) Benzene tends to undergo substitution rather than addition reactions, even though it has

a high index of hydrogen deficiency. B) All of the hydrogen atoms of benzene are equivalent. C) The carbon-carbon bonds of benzene are alternately short and long around the ring. D) Only one o-dichlorobenzene has ever been found. E) Benzene is more stable than the hypothetical compound 1,3,5-cyclohexatriene.

Ans: C Topic: Bonding and Resonance

2. Which of the following is true of benzene? A) Benzene tends to undergo addition rather than substitution reactions. B) All of the hydrogen atoms of benzene are equivalent. C) The carbon-carbon bonds of benzene are alternately short and long around the ring. D) The benzene ring is a distorted hexagon. E) Benzene has the stability expected for cyclohexatriene.

Ans: B Topic: Bonding and Resonance

3. The carbon-carbon bonds in benzene are: A) of equal length and are shorter than the double bond of ethene. B) of equal length and are intermediate between a double bond and a single bond. C) of unequal length and are alternately short and long around the ring. D) due only to p-orbital overlap. E) of equal length and intermediate between the carbon-carbon bond lengths in ethene and

ethyne. Ans: B

Topic: Nomenclature, Bonding and Resonance

4. In which of the following compounds would the shortest carbon-carbon bond(s) be found?

A) Toluene B) 2-Ethylcyclopentene C) 4-Methyl-1,3-cyclohexadiene D) 3-Methyl-1-hexyne E) 3-Methyl-1,3-hexadiene

Ans: D

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Topic: Bonding and Resonance

5. We now know that the two Kekule structures for benzene are related in the following way:

A) They are each equally correct as a structure for benzene. B) Benzene is sometimes one structure and sometimes the other. C) The two structures are in a state of rapid equilibrium. D) Neither of the two structures adequately describes benzene; benzene is a resonance

hybrid of the two. E) None of the above

Ans: D Topic: Nomenclature, Bonding and Resonance

6. In which of the following compounds would the longest carbon-carbon bond(s) be found?

A) 2-bromobenzaldehyde B) Vinylbenzene C) 1,3,5-heptatriene D) 2,4,6-octatriene E) 2-Ethylbenzoic acid

Ans: D Topic: Aromatic/ Antiaromatic/ Nonaromatic

7. Which of the following statements regarding the cyclopentadienyl radical is correct? A) It is aromatic. B) It is not aromatic. C) It obeys Huckel's rule. D) It undergoes reactions characteristic of benzene. E) It has a closed shell of 6 pi-electrons.

Ans: B

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Topic: Aromaticity, Huckel Rule

8. Which of the following would you expect to be aromatic?

I II III IV V

H

H

A) I B) II C) III D) IV E) V

Ans: E Topic: Aromaticity, Huckel Rule

9. Which of these would you expect to have significant resonance stabilization energy?

I II III

NNH

A) I B) II C) III D) All of the above E) None of the above

Ans: D

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Topic: Aromaticity, Huckel Rule

10. Of the following C-10 compounds, which is expected to possess the greatest resonance (delocalization) energy?

I II III IV VA) I B) II C) III D) IV E) V

Ans: C Topic: Aromaticity, Huckel Rule

11. Which of the following would you expect to be aromatic?

IVI II III

H H

A) I B) II C) III D) IV E) None of these

Ans: B

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Topic: Aromaticity, Huckel Rule

12. Which compound would you NOT expect to be aromatic?

IVI II III V

NS N O B

H R

A) I B) II C) III D) IV E) V

Ans: E Topic: Aromaticity, Huckel Rule

13. Which annulene would you NOT expect to be aromatic? A) [6]-Annulene B) [14]-Annulene C) [16]-Annulene D) [18]-Annulene E) [22]-Annulene

Ans: C Topic: Aromaticity, Huckel Rule

14. Which of the following would you expect to be aromatic?

IVI II IIIA) I B) II C) III D) IV E) All of these

Ans: A

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Topic: Aromaticity, Huckel Rule

15. Which of these species is aromatic?

IVI II III V

NH O N

H

O

O

O

S

A) I B) II C) III D) IV E) V

Ans: B Topic: Aromaticity, Huckel Rule

16. Which of the following structures would be aromatic?

IVI II III V

-2

2K

KK Br Br

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Aromaticity, Huckel Rule

17. Which of the following would you expect to be antiaromatic?

IVI II III VA) I B) II C) III D) IV E) V

Ans: C Topic: Aromaticity, Huckel Rule

18. Which of the following would you expect to be aromatic?

IVI II III

H H

A) I B) II C) III D) IV E) None of the above

Ans: C

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Topic: Aromaticity, Huckel Rule

19. On the basis of molecular orbital theory and Huckel's rule, which molecules and/or ions should be aromatic?

IVI II III V

H H H H

N

H H H H

VI VII VIII IX

A) I and V B) III and VIII C) IV, VII and IX D) IV, VI, VII and IX E) All of the structures, I-IX

Ans: D Topic: Aromaticity, Huckel Rule

20. On the basis of molecular orbital theory and Huckel's rule, which of these compounds should be aromatic?

HH

I II III IV VA) I B) II C) III D) IV E) V

Ans: E

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Topic: Aromaticity, Huckel Rule

21. Of Huckel's requirements for aromatic character, only this one is waived in the case of certain compounds considered to be aromatic.

A) The ring system must be planar. B) The system must be monocyclic. C) There must be (4n + 2) π electrons. D) The Huckel number of electrons must be completely delocalized. E) None. All of these rules must apply in every case.

Ans: B Topic: Aromaticity, Huckel Rule

22. Which of these is an aromatic molecule?

I II III IV V

N O BS

CH3 CH3 ONH

A) I B) II C) III D) IV E) V

Ans: A Topic: Aromaticity, Huckel Rule

23. In which case is the indicated unshared pair of electrons NOT a contributor to the π aromatic system?

I II III IV

N OH

NH

A) I B) II C) III D) IV E) None of these

Ans: B

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Topic: Chemical Tests and Reactions

24. Which reagent(s) would serve as the basis for a simple chemical test that would distinguish between benzene and 1-hexene?

A) NaOH in H2O B) Br2 in CCl4 C) AgNO3 in C2H5OH D) NaHSO3 in H2O E) None of these

Ans: B Topic: Chemical Tests and Reactions

25. Which reagent(s) would serve as the basis for a simple chemical test that would distinguish between ethylbenzene and vinylcyclohexane?

A) H2CrO4 B) LAH C) NaBH4, H2O D) KMnO4, OH−, H2O E) Two of the above

Ans: D Topic: Chemical Tests and Reactions

26. Which reagent(s) would serve as the basis for a simple chemical test that would distinguish between naphthalene and 2,4,6-decatriene?

A) NaOH in H2O B) KMnO4, OH−, H2O C) NaBH4, H2O D) H2CrO4 E) None of these

Ans: B Topic: Chemical and Spectroscopic Analysis

27. Which reagent(s)/technique would serve to distinguish between azulene and bicyclo[5.3.0]decane?

A) Br2, CCl4 B) KMnO4, OH−, H2O C) NMR Spectroscopy D) UV Spectroscopy E) Two of these

Ans: E

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Topic: Chemical Tests and Reactions

28. Which is the only one of these reagents which will react with benzene under the specified conditions?

A) Cl2, FeCl3, heat B) H2, 25°C C) Br2/CCl4, 25°C, dark D) KMnO4/H2O, 25°C E) H3O+, heat

Ans: A Topic: Nomenclature and Isomerism

29. Which dibromobenzene can, in theory, yield three mononitro derivatives? A) o-Dibromobenzene B) m-Dibromobenzene C) p-Dibromobenzene D) All of these E) None of these

Ans: B Topic: Nomenclature and Isomerism

30. If thiophene is an aromatic molecule and reacts similarly to benzene, how many (neutral) monobromothiophenes could be obtained in the following reaction?

S Br2FeBr3

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: B

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Topic: Nomenclature and Isomerism

31. 2-Bromo-4-nitroaniline is:

IV

I II

V

III

NO2

BrOCH3

NH2

NO2

Br

NH2

Br

NO2

NO2

H2N

Br

NO2

H3COBr

A) I B) II C) III D) IV E) V

Ans: C Topic: Nomenclature and Isomerism

32. 4-Bromo-2-nitroaniline is:

IV

I II

V

III

NO2

BrOCH3

NH2

NO2

Br

NH2

Br

NO2

NO2

H2N

Br

NO2

H3COBr

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Nomenclature and Isomerism

33. 4-Amino-2-chlorophenol is:

IV

I II

V

III

NH2

ClOH

NO2

O

ClNH2

Cl OHO

Cl

H2N

NO2

ClOH

A) I B) II C) III D) IV E) V

Ans: D Topic: Nomenclature and Isomerism

34. 4-Chloro-3-nitro-benzaldehyde is:

IV

I II

V

III

NH2

ClOH

NO2

O

ClNH2

Cl OHO

Cl

H2N

NO2

ClOH

A) I B) II C) III D) IV E) V

Ans: B

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Topic: Nomenclature and Isomerism

35. 4-amino-2-chlorobenzaldehyde is:

IV

I II

V

III

NH2

ClOH

NO2

O

ClNH2

Cl OHO

Cl

H2N

NO2

ClOH

A) I B) II C) III D) IV E) V

Ans: C Topic: Nomenclature and Isomerism 36. 4-amino-2-bromoanisole is:

IV

I II

V

III

NH2

BrOCH3

NO2

Br

H3CONH2

Br OCH3O

Br

H2N

NO2

BrOCH3

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Nomenclature and Isomerism

37. 4-bromomethyl-2-nitroanisole is:

IV

I II

V

III

NH2

BrOCH3

NO2

Br

H3CONH2

Br OCH3O

Br

H2N

NO2

BrOCH3

A) I B) II C) III D) IV E) V

Ans: B Topic: Nomenclature and Isomerism

38. How many different dibromophenols are possible? A) 8 B) 7 C) 6 D) 5 E) 4

Ans: C Topic: Nomenclature and Isomerism

39. The correct name for the compound shown below is:

Br

NH2

Br

A) 3,4-Dibromoaniline B) 2,4-Dibromoaniline C) 2,5-Dibromoaniline D) 3,6-Dibromoaniline E) 2,6-Dibromoaniline

Ans: C

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Topic: Nomenclature and Isomerism

40. Which dibromobenzene can yield only one mononitro derivative? A) o-Dibromobenzene B) m-Dibromobenzene C) p-Dibromobenzene D) More than one of these E) None of these

Ans: C Topic: Nomenclature and Isomerism

41. A dichlorobenzene that on reaction with nitric acid and sulfuric acid might theoretically yield three mononitro products would be:

A) o-Dichlorobenzene B) m-Dichlorobenzene C) p-Dichlorobenzene D) None of these E) All of these

Ans: B Topic: Nomenclature and Isomerism

42. In theory, a single molecule of this compound will rotate plane-polarized light. A) Butylbenzene B) Isobutylbenzene C) sec-Butylbenzene D) tert-Butylbenzene E) None of these

Ans: C

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Topic: Nomenclature and Isomerism

43. Which of the following is NOT 2-bromo-5-nitrobenzoic acid?

IV

I II

V

III

NO2

Br

HO

O

Br

O2N OH

O

Br

NO2HO

O

NO2

Br

HO

O

Br

HO O

A) I B) II C) III D) IV E) V

Ans: D Topic: Nomenclature and Isomerism

44. Toluene is the name commonly assigned to: A) Hydroxybenzene B) Aminobenzene C) Methylbenzene D) Ethylbenzene E) Methoxybenzene

Ans: C Topic: Nomenclature and Isomerism

45. Anisole is the name commonly assigned to: A) Hydroxybenzene B) Aminobenzene C) Methylbenzene D) Ethylbenzene E) Methoxybenzene

Ans: E

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Topic: Nomenclature and Isomerism

46. Phenol is the name commonly assigned to: A) Hydroxybenzene B) Aminobenzene C) Methylbenzene D) Ethylbenzene E) Methoxybenzene

Ans: A Topic: Nomenclature and Isomerism

47. Aniline is the name commonly assigned to: A) Hydroxybenzene B) Aminobenzene C) Methylbenzene D) Ethylbenzene E) Methoxybenzene

Ans: B Topic: Nomenclature and Isomerism

48.

The complete name for the following compound is:

CH3

H

A) sec-Hexylbenzene B) 2-Phenylhexane C) (R)-2-Phenylhexane D) (S)-2-Phenylhexane E) Butylmethylphenylmethane

Ans: D Topic: Nomenclature and Isomerism

49. How many dichloronaphthalenes are possible? A) 7 B) 8 C) 9 D) 10 E) 12

Ans: D

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Topic: Nomenclature and Isomerism

50. Which of these is the single best representation for naphthalene?

V

III

IV

III

A) I B) II C) III D) IV E) V

Ans: A Topic: Molecular Orbital Theory

51. How many equivalent resonance structures can be written for the cyclopentadienyl anion?

A) 3 B) 4 C) 5 D) 6 E) 7

Ans: C Topic: Molecular Orbital Theory

52. In the molecular orbital model of benzene, the six p-orbitals combine to form how many molecular orbitals?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: A

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Topic: Molecular Orbital Theory

53. Consider the molecular orbital model of benzene. In the ground state how many molecular orbitals are filled with electrons?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C Topic: Molecular Orbital Theory

54. In the molecular orbital model of benzene, how many pi-electrons are delocalized about the ring?

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: E Topic: Molecular Orbital Theory

55. In the molecular orbital model of benzene, how many pi-electrons are in bonding molecular orbitals?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: A Topic: Molecular Orbital Theory

56. Consider the molecular orbital model of cyclopentadienyl anion. In the ground state how many molecular orbitals are filled with electrons?

A) 1 B) 2 C) 3 D) 4 E) 5

Ans: C

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Topic: Molecular Orbital Theory

57. In the molecular orbital model of cyclopentadienyl anion, how many pi-electrons are delocalized about the ring?

A) 2 B) 3 C) 4 D) 5 E) 6

Ans: E Topic: Molecular Orbital Theory

58. In the molecular orbital model of cyclopentadienyl anion, how many pi-electrons are in bonding molecular orbitals?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: A Topic: Molecular Orbital Theory

59. In the molecular orbital model of cycloheptadienyl cation, how many pi-electrons are in bonding molecular orbitals?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: A Topic: Molecular Orbital Theory

60. In the molecular orbital model of cycloheptadienyl cation, how many pi-electrons are delocalized about the ring?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: A

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Topic: Molecular Orbital Theory

61. In the molecular orbital model of 1,3-cyclobutadiene, how many electrons are in non-bonding molecular orbitals?

A) 6 B) 5 C) 4 D) 3 E) 2

Ans: E Topic: Molecular Orbital Theory

62. In the molecular orbital model of which of the following substance(s) are non-bonding orbitals found?

A) 1,3-Cyclobutadiene B) Cyclopentadienyl anion C) 1,3,5,7-Cyclooctatetraene D) Two of the above E) All of the above

Ans: D Topic: Molecular Orbital Theory

63. Which cyclization(s) should occur with a decrease in pi-electron energy?

I

II

III

IV

CH2 CH CH CH2 + H2

CH2 CH CH2 + H2

CH2 CH CH2 + H2

CH2 CH CH2 + H2

A) I B) II C) III D) IV E) All of the above

Ans: B

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Topic: Molecular Orbital Theory

64. Application of the polygon-and-circle technique reveals that single electrons occupy each of the two nonbonding orbitals in the molecular orbital diagram of:

A) Cyclobutadiene B) Benzene C) Cyclopropenyl cation D) Cyclopentadienyl anion E) Cycloheptatrienyl cation

Ans: A Topic: Explanations and Predictions

65. Why would 1,3-cyclohexadiene undergo dehydrogenation readily? A) It is easily reduced. B) Hydrogen is a small molecule. C) 1,3-Cyclohexadiene has no resonance energy. D) It would gain considerable stability by becoming benzene. E) It would not undergo dehydrogenation.

Ans: D Topic: Explanations and Predictions

66. Which of the following statements about cyclooctatetraene is NOT true? A) The compound rapidly decolorizes Br2/CCl4 solutions. B) The compound rapidly decolorizes aqueous solutions of KMnO4. C) The compound readily adds hydrogen. D) The compound is nonplanar. E) The compound is comparable to benzene in stability.

Ans: E Topic: Explanations and Predictions

67. Cyclopentadiene is unusually acidic for a hydrocarbon. An explanation for this is the following statement.

A) The carbon atoms of cyclopentadiene are all sp2-hybridized. B) Cyclopentadiene is aromatic. C) Removal of a proton from cyclopentadiene yields an aromatic anion. D) Removal of a hydrogen atom from cyclopentadiene yields a highly stable free radical. E) Removal of a hydride ion from cyclopentadiene produces an aromatic cation.

Ans: C

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Topic: Explanations and Predictions

68. Recalling that benzene has a resonance energy of 152 kJ mol-1 and naphthalene has a resonance energy of 255 kJ mol-1, predict the positions which would be occupied by bromine when phenanthrene (below) undergoes addition of Br2.

1

23 4 5 6

78

910

A) 1, 2 B) 1, 4 C) 3, 4 D) 7, 8 E) 9, 10

Ans: E Topic: Spectroscopy

69. Which isomer of C7H7Cl exhibits strong IR absorbances at 690 and 750 cm1?

I II III IV

CH3Cl

CH3

Cl

CH3

Cl

CH2Cl

A) I B) II C) III D) IV E) II and IV

Ans: E

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Topic: Spectroscopy

70. Which of these compounds absorbs at the longest wavelength in the UV-visible region?

I II III IV VA) I B) II C) III D) IV E) V

Ans: B Topic: Spectroscopy

71. A compound has the formula C8H9Br. Its 1H NMR spectrum consists of: doublet, δ 2.0 quartet, δ 5.15 multiplet, δ 7.35 The IR spectrum shows two peaks in the 680-840 cm-1 region; one is between 690 and 710 cm-1 and the other is between 730 and 770 cm-1. Which is a possible structure for the compound?

I

Br

II

Br

III

Br

IV

Br

VBr

A) I B) II C) III D) IV E) V

Ans: D

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Topic: Spectroscopy

72. Which of the following substances, formula C8H9Br, might exhibit the following 1H NMR spectrum ? triplet, δ 2.8 triplet, δ 4.65 multiplet, δ 7.2

I

Br

II

Br

III

Br

IV

Br

VBr

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Spectroscopy

73. Which of the following substances, formula C8H9Br, might exhibit the following 1H NMR spectrum ? triplet, δ 1.2 quartet, δ 2.45 multiplet, δ 7.4

I

Br

II

Br

III

Br

IV

Br

VBr

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Spectroscopy

74. Which of the following substances, formula C8H9Br, might exhibit the following 1H NMR spectrum ? singlet, δ 2.45 singlet, δ 2.5 multiplet, δ 7.35

I

Br

II

Br

III

Br

IV

Br

VBr

A) I B) II C) III D) IV E) V

Ans: E Topic: Spectroscopy

75. Which of the following substances, C8H9Cl, would exhibit five signals in its 13C NMR spectrum?

I II

Cl

III

IV

Cl

VCl

ClCl

A) I B) II C) III D) IV E) V

Ans: C

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Topic: Spectroscopy

76. Which of the following substances, C9H10O, would exhibit seven signals in its 13C NMR spectrum?

I II III

O

IV V

O

O

HO O

A) I B) II C) III D) IV E) V

Ans: A Topic: Spectroscopy

77. For which of the following substances, C9H10O, would the aromatic multiplet, in its 1H NMR spectrum, consist of two doublets?

I II III

O

IV V

O

O

HO O

A) I B) II C) III D) IV E) V

Ans: A

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Topic: Spectroscopy

78. In the 1H NMR spectra of which of the following substances, C9H10O, would you expect to see two singlets in the range of δ 2.0-2.5 ppm?

I II III

O

IV V

O

O

HO O

A) I and III B) I, II, and III C) IV D) V E) All of the above substances would exhibit two singlets δ 2.0-2.5 ppm in their 1H NMR

spectra Ans: B

SHORT ANSWER QUESTIONS Topic: General Concepts

79. A compound that reacts like an alkane, alkene, alkyne, or one of their derivatives, is called an _____________ compound, while one that reacts like benzene is called an _____________ compound. Ans: aliphatic, aromatic

Topic: Nomenclature

80. When a benzene ring is used as a substituent, it is called a _________ group. Ans: phenyl

Topic: General Concepts

81. The difference between the amount of heat actually released upon hydrogenation of benzene and that calculated on the basis of the Kekule structure is called the ____________________ of benzene. Ans: resonance energy

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Topic: General Concepts

82. Molecular orbitals of equal energy are referred to as _________ orbitals. Ans: degenerate

Topic: Huckel’s rule

83. Hückel's Rule requires _________ π electrons for an aromatic compound. Ans: 4n+2

Topic: General Concepts

84. Monocyclic compounds with alternating single and double bonds are called __________. Ans: annulenes

Topic: General Concepts

85. Cagelike molecules with the geometry of a truncated icosahedron are called ___________. Ans: fullerenes

Topic: Aromaticity, Reactivity

86. Pyrrole is not particularly basic, because the lone pair on the nitrogen is ______________. Ans: part of the aromatic system

Topic: General Concepts

87. Humans do not have the biochemical ability to synthesize the benzene ring. Therefore, two amino acids, _____________ and ___________, are essential to the human diet. Ans: tryptophan, phenylalanine

Topic: Aromaticity, Reactivity

88. Benzene, while unusually unreactive, will react under certain conditions. However, when it does react, it does so by ___________ rather than by addition. Ans: substitution

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Topic: Nomenclature

89. Draw the structure corresponding to the following name: 2-bromo-5-nitrophenol Ans: OH

Br

O2N Topic: Nomenclature

90. Draw the structure corresponding to the following name: 3-bromo 5-phenylacetophenone Ans: NH2

Br

Topic: Nomenclature

91. Draw the structure corresponding to the following name: 2-hydroxy-4-(3-methylcyclopentyl)benzoic acid Ans: HO

HO2C

Topic: Nomenclature

92. Draw the structure corresponding to the following name: 3-nitro-4-iodoanisole Ans: OO2N

I Topic: Nomenclature

93. Give the IUPAC name for the following substance:

O

OH

Ans: 2-methyl-4-(3-methylbutyl)benzoic acid

Topic: Resonance

94. Draw all significant resonance structures for pyridine, C6H5N Ans:

N N....

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Topic: Resonance

95. Draw all significant resonance structures for azulene, C10H8 Ans:

Topic: Aromaticity

96. Briefly explain why the aromatic hydrocarbon azulene, C10H8, possesses a significant dipole moment. Use diagrams as needed to illustrate/clarify your answer. Ans: Azulene has the bicyclic structure shown below. Since the “non-polar” resonance

hybrid meets the Huckel rule for aromaticity, it accounts for the observed aromatic properties of azulene. However, closer scrutiny suggests that a shift in electron density, in which the 7-membered ring is electron deficient and the 5-membered ring is electron-rich would be especially stable: each ring is now independently aromatic, an aromatic cycloheptatrienyl cation fused with an aromatic cyclopentadienyl anion. Thus, the most stable pi-electron distribution would suggest a polar structure for azulene, accounting for this substance having a significant dipole moment.

non-polar polar Topic: Aromaticity, Molecular Orbital Theory

97. Use the “polygon-in-circle” method to draw an MO diagram showing the pi-electron distribution pattern in the cyclopentadienyl anion. How is this diagram useful in explaining the aromatic properties of this anion? Ans: The following MO diagram can be generated using the polygon-in-circle method.

The six pi electrons of the cyclopentadienyl anion in the bonding molecular orbitals form a closed bonding shell, accounting for its aromatic properties.

Bonding MO

Antibonding MO

6 pi electrons"closed bonding shell"

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Topic: Aromaticity, Reactivity

98. Explain briefly why cyclopentadiene readily reacts with strong bases. Ans: The acidity of a substance can be often be correlated with the stability of its

conjugate base: substances that have exceptionally stable conjugate bases tend to be strong acids. The conjugate base of cyclopentadiene, formed during reaction with a base, is exceptionally stable, by virtue of being an aromatic anion (6 pi electrons, planar ring), thus accounting for the readiness with which cyclopentadiene reacts with bases.

HH

B:−

H

..Aromaticanion

Topic: Resonance, Bond Lengths

99. Although all bond lengths in benzene are identical, that is not always true for all aromatic compounds. In naphthalene, for instance, the C1-C2 bond is shorter than the C2-C3 bond. Explain, using resonance theory. Ans: The major resonance structures for naphthalene are drawn below. The observed

bond lengths reflect the contribution of each structure to the overall resonance hybrid: The C1-C2 bond: two double bonds (I and II), and one single bond (III) The C2-C3 bond: one double bond (III), and two single bonds (I and II) Overall: C1-C2 bond more double-bond-like, thus shorter.

II III IVI

123

123

123

123

shorter

longer

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Topic: Aromaticity, Resonance Stabilization Energy

100. The heats of hydrogenation for cyclohexene and benzene are given below. Calculate the resonance stabilization energy of benzene. C6H10 + H2 C6H12 ΔHo = -120 kJ/mol C6H6 + 3H2 C6H12 ΔHo = -208 kJ/mol Ans: The resonance stabilization energy of benzene is the difference between the

theoretical and observed ΔHo values. Hydrogenation of three double bonds should release 3 times the energy released when one double bond is hydrogenated. Thus, the theoretical ΔHo for benzene can be calculated as [3x (-120)] kJ/mol = -360 kJ/mol Therefore, Resonance stabilization energy of benzene = (-208) – (-360) kJ/mol = 152 kJ/mol

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Topic: Aromaticity, Reactivity

101. The Lewis structures of both pyridine and pyrrole have an electron pair on the nitrogen atom, suggesting that both substances might possess basic properties. However, only pyridine reacts readily with HCl to form pyridinium chloride, while pyrrole is rather unreactive. Explain clearly, using relevant diagrams to illustrate/clarify your answer. Ans:

N..sp2

+ HClNH

+ Cl−

pyridinium chloride

N H..p

+ HCl X

pyrrole electron pair:part of aromatic pi sextet

pyridinium chloride

NH

H

not aromatic

+ Cl−

Both pyridine and pyrrole are known to exhibit aromatic properties; the nitrogen atom must therefore be sp2 hybridized in both cases. In the pyridine molecule, this places the electron pair in an sp2 hybrid orbital, and not involved in the aromatic π sextet needed for aromatic stability; the electron pair is thus “available” for reacting with HCl, forming pyridinium chloride, while preserving aromatic stability. By contrast, the electron pair in pyrrole must be placed in the p orbital, since all three sp2 orbitals are used in sigma bonds with neighboring atoms. This allows the electron pair to contribute to aromatic stability by becoming part of the aromatic sextet. Thus, the electron pair on nitrogen is not “available” for reacting with HCl, because doing so would destroy the aromaticity of the ring.

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Topic: Aromaticity, Bonding

102. Consider the oxygen atom in the molecules of furan and tetrahydrofuran. Bearing in mind that furan exhibits aromatic properties, compare the hybridization of oxygen in both species, explaining why it must be different, although at first glance, it may appear identical.

O O.. ..

....

THFFuran Ans:

O

Tetrahydrofuran: sp3 hybridized both electron pairs in sp3 orbitals

O..p

Furan: sp2 hybridizedone electron pair in p orbital:part of aromatic pi sextet

.. sp2....

sp3

sp3

Oxygen has 2 lone electron pairs in both species and, at first glance, it might appear that the hybridization patterns are identical. In THF, the oxygen atom is sp3 hybridized and both pairs can be placed in sp3 hybrid orbitals. In furan, there are two possibilities that must be considered: i) the oxygen may be sp3 hybridized, with both electron pairs sp3 hybrid orbitals, as in THF, or, ii) oxygen may be sp2 hybridized, with one electron pair in an sp3 hybrid orbital, the other in a p orbital. In the latter case, the electrons in the p orbital can then become part of an aromatic sextet, allowing the molecule to gain aromatic stability. Since furan is known to exhibit markedly aromatic properties, the oxygen must be sp2 hybridized.

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MULTIPLE CHOICE QUESTIONS

Topic: Reaction Products

1. The major product(s), A, of the following reaction,

CH3CH2Cl2, hν

400 - 600 oC

CH3CH2 CH3CH2 CH3CHClCH2CH2Cl

Cl ClI II III IV

A

would be: A) I B) II C) A mixture of I and II D) III E) IV Ans: E

Topic: Reaction Products

2. What would be the major product(s) of the following reaction?

CO2H

NO2

I II III

CO2H

NO2NO2

CO2H

NO2

NO2

CO2H

NO2O2N

O2NCO2H

NO2

IV

HNO3H2SO4, heat

?

A) I B) II C) III D) IV E) Equal amounts of II and IV Ans: C

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Topic: Reaction Products

3. The major product(s), C, of the following reaction,

Cl

Cl

SO3H2SO4

C

Cl

Cl

Cl

Cl

Cl

Cl

SO3H

SO3HHO3S

I II III

would be: A) I B) II C) III D) Equal amounts of I and II E) Equal amounts of I and III Ans: B

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Topic: Reaction Products

4. The major product(s), D, of the following reaction,

C

O

CH2

CO

CH2 CO

CH2

CO

CH2 CO

CH2

Br

Br

Br

Br

Br2

FeBr3D

I II

III IV

would be: A) I B) II C) III D) IV E) Equal amounts of I and II Ans: D

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Topic: Reaction Products

5. What would be the product of the following reaction sequence?

IV

OH

O

I II

V

III

OH

OO OH

i) SOCl2ii) C6H6, AlCl3iii) Zn(Hg), HCl, heat

?

A) I B) II C) III D) IV E) V Ans: E

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Topic: Reaction Products

6. What would you expect to be the major product obtained from the following reaction?

COOH

SO3H

COOH

SO3H

COOH

SO3H

COOH

SO3H

COOH

SO3H

Br

BrBr

Br

I II III IV

Br2

FeBr3?

A) I B) II C) III D) IV E) Equal amounts of II and IV Ans: C

Topic: Reaction Products

7. What would be the major product of the following reaction?

CH2CH2CH3

CH2CH2CH3 CH2CH2CH3 CHCH2CH3

CH2CHCH3 CH2CH2CH2Cl

Cl

Cl Cl

Cl

Cl2400 oC

?

I II III

IV VA) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

8. What would you expect to be the major product obtained from the following reaction?

NO2

SO3H

NO2

SO3H

NO2

SO3H

NO2

SO3H

NO2

SO3H

Br

BrBr

Br

I II III IV

Br2

FeBr3?

A) I B) II C) III D) IV E) Equal amounts of II and IV Ans: C

Topic: Reaction Products

9. What would you expect to be the major product obtained from the following reaction?

HN

O

I

IV

II

V

HN

OO2N

HN

O

O2N

HN

O

NO2

HN

O

NO2

III

HN

ONO2

?HNO3H2SO4, heat

A) I B) II C) III D) IV E) V Ans: E

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Topic: Reaction Products

10. What would be the major product(s) of the following reaction?

NO2

O

I II III

NO2SO3H

O

NO2

SO3HO

NO2HO3S

OHO3S

NO2

O

IV

?H2SO4

A) I B) II C) III D) Equal amounts of IV E) Equal amounts of II and IV Ans: C

Topic: Reaction Products

11. What would you expect to be the major product obtained from the mononitration of m-dichlorobenzene?

I II III

Cl

ClNO2

Cl

Cl

NO2

Cl

ClO2N

A) I B) II C) III D) Equal amounts of I and II E) Equal amounts of I, II and III Ans: B

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Topic: Reaction Products

12. What would you expect to be the major product obtained from the following reaction?

I IIIII IV

SO3HNO2

HO O

SO3H

NO2

HO O

SO3HO2N

HO OO2N

SO3H

HO O

SO3H

HO OHNO3 H2SO4 , heat

?

A) I B) II C) III D) IV E) Equal amounts of I and II Ans: C

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Topic: Reaction Products

13. What product would result from the following series of reactions,

?

i) AlCl3ii) N-Bromosuccinimide, peroxidesiii) CH3ONa, CH3OH, heativ) MMPPv) CH3MgBrvi) NH4Cl

+Cl

I

IV

II

V

IIIHO

HO

HO HO

Br

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products

14. The major product(s), D, of the following reaction

O

O O

OO

O2N

NO2

NO2

NO2

HNO3

H2SO4D

I II

III IV

would be: A) I B) II C) III D) IV E) Equal amounts of I and II Ans: D

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Topic: Reaction Products

15. What would be the major product of the following reaction?

I

IV

II

V

Br

Br

BrBr

III

Br

?NBS, ROORlight

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

16. Which would be the major product(s) of the following reaction? HO O

I

HNO3 H2SO4

II

HO ONO2

NO2

HO O

HO3S

HO O

III

?

A) I B) II C) III D) I and II in roughly equal amounts E) I and III in roughly equal amounts Ans: A

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Topic: Reaction Products

17. Which would be the product, X, of the following reaction sequence?

IV

OH

O

I II

O

SO2 CO2

V

CH2

III

?i) SOCl2ii) benzene, AlCl3iii) Zn(Hg), HCl

A) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

18. Toluene is subjected to the action of the following reagents in the order given: (1) KMnO4,OH-, heat; then H3O+ (2) HNO3, H2SO4 (3) Br2, FeBr3 What is the final product of this sequence?

I II III

CO2H

BrNO2

CO2H

Br NO2

CO2HNO2

Br

IV VNO2

Br

CO2H

NO2BrCH3

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

19. When toluene is reacted in turn with 1) Cl2 (large excess), heat, and light and 2) Br2,FeBr3, the chief product is:

I

Br

Cl

II

CCl3

Br

III

CCl3Br

IV

Br

CCl3

A) I B) II C) III D) IV E) A mixture of III and IV Ans: B

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Topic: Reaction Products

20. The reaction of benzene with (CH3)3CCH2Cl in the presence of anhydrous aluminum chloride produces principally which of these?

IV V

I II III

A) I B) II C) III D) IV E) V Ans: E

Topic: Reaction Products

21. What might be predicted to happen when the following substance undergoes Friedel-Crafts acylation?

CH2O2N

A B A) Substitution occurs in ring B, p- to the methylene group B) Substitution occurs in ring A, o- to the nitro group C) Substitution occurs in ring A, o- to the methylene group D) Substitution occurs in ring B, m- to the methylene group E) None of the above. No reaction will occur. Ans: A

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Topic: Nomenclature, Reaction Products

22. A mixture of chlorobenzene (1 mol) and acetanilide (1mol) is allowed to react with Br2 (0.5 mol) in the presence of trace amounts of FeBr3. What is the principal product of the competing reactions? A) 1-bromo-4-chlorobenzene B) 1-bromo-2-chlorobenzene C) 1-bromo-3-chlorobenzene D) 4-bromoacetanilide E) 3-bromoacetanilide Ans: D

Topic: Nomenclature, Reaction Products

23. What is the chief product of the Friedel-Crafts alkylation of benzene with 1-butene and AlCl3? A) butylbenzene B) 2-phenylbutane C) 2-methyl-1-phenylpropane D) t-butylbenzene E) 2,2-diphenylbutane Ans: B

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Topic: Reaction Products

24. Which of the following reactions would give the product(s) indicated in substantial amounts (i.e., in greater than 50% yield)?

+ CH3Cl

NH2AlCl3

NH2 NH2

and

CH3

CH3

NH2 NH2

+ CH3ClAlCl3

CH3

+ CH3CH2CH2ClAlCl3 CH2CH2CH3

I

II

III

A) I B) II C) III D) All of these E) None of these Ans: E

Topic: Reagents

25. Which reagent(s) would you use to carry out the following transformation? toluene ⎯⎯⎯→ benzoic acid A) Br2, heat, and light B) Cl2, FeCl3 C) KMnO4, OH-, heat (then H3O+) D) HNO3/H2SO4 E) SO3/H2SO4 Ans: C

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26. Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯⎯→ 1-chloro-1-phenylethane A) Cl2, light, and heat B) Cl2, FeCl3 C) SOCl2 D) C2H5Cl, AlCl3 E) HCl, O2 Ans: A

Topic: Reagents

27. Which reagent(s) would you use to carry out the following transformation? isopropylbenzene ⎯⎯⎯→ 2- and 4-chloro-1-isopropylbenzene A) Cl2, light, and heat B) Cl2, FeCl3 C) SOCl2 D) C2H5Cl, AlCl3 E) HCl, peroxides Ans: B

Topic: Reagents

28. Which reagent would you use to carry out the following transformation? tert-butylbenzene ⎯⎯⎯→ p-tert-butylbenzenesulfonic acid + o-tert-butylbenzenesulfonic acid

A) HNO3/H2SO4 B) tert-C4H9Cl/AlCl3 C) H2SO3/peroxides D) SO3/H2SO4 E) SO2/H2SO3 Ans: D

Topic: Reagents

29. Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯⎯⎯→ benzoic acid A) Cl2, light, and heat B) Cl2, FeCl3 C) KMnO4, OH-, heat (then H3O+) D) HNO3/H2SO4 E) SO3/H2SO4 Ans: C

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Topic: Reagents

30. Which reagent(s) would you use to carry out the following transformation? ethylbenzene ⎯⎯→ 2- and 4-chloro-1-ethylbenzene A) Cl2, light, and heat B) Cl2, FeCl3 C) SOCl2 D) C2H5Cl, AlCl3 E) None of these Ans: B

Topic: Reagents

31. Which reagent(s) would you use to carry out the following transformation? t-butylbenzene ⎯⎯⎯→ p-chloro substitution product A) Cl2, light, and heat B) Cl2, FeCl3 C) SOCl2 D) C2H5Cl, AlCl3 E) HCl, peroxide Ans: B

Topic: Reagents

32. Which reagent(s) would you use to carry out the following transformation? toluene ⎯⎯⎯→ benzyl bromide A) Br2, FeBr3 B) N-Bromosuccinimide, ROOR, hν C) HBr D) Br2/CCl4 E) NaBr, H2SO4 Ans: B

Topic: Reagents

33. Which reagent(s) would you use to synthesize 2- and 4-bromo-1-cyclopentylbenzene from cyclopentylbenzene? A) N-Bromosuccinimide (NBS), CCl4, light B) PBr3 C) Br2, FeBr3 D) CH3CH2Br, AlBr3 E) HBr, ROOR Ans: C

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Topic: Reagents

34. The compound 4-bromo-1-propylbenzene is best made from benzene by the application of these reagents in the order shown: A) (1) Br2,Fe (2) CH3CH2CH2Cl, AlCl3 B) (1) CH3CH2CH2Cl, AlCl3 (2) Br2,Fe C) CH3CH2CCl

O

1) , AlCl3 2) Br2, Fe 3) Zn(Hg), HCl

D) CH3CH2CCl

O

1) , AlCl3 3) Br2, Fe2) Zn(Hg), HCl

E) (1) (CH3)2CHCl, AlCl3 (2) Br2,Fe Ans: D

Topic: Functional Group Tests

35. Which reagent would you use as the basis for a simple chemical test that would distinguish between toluene and vinylbenzene (C6H5CH=CH2)? A) NaOH/H2O B) Br2/CCl4 C) NaBH4 D) HCl/H2O E) NaI in acetone Ans: B

Topic: Nomenclature, Functional Group Tests

36. Which reagent or test could you use to distinguish between phenylacetylene and vinylbenzene? A) NaOH/H2O B) Br2/CCl4 C) IR Spectroscopy D) CrO3/H2SO4 E) Concd. H2SO4 Ans: C

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Topic: Nomenclature, Synthesis

37. Which of the following would be the best synthesis of 1,4-dimethyl-2-nitrobenzene? A)

BenzeneHNO3

H2SO4

product2 CH3Cl

2 AlCl3B)

TolueneHNO3

H2SO4

productCH3Cl

AlCl3C)

p-XyleneHNO3

H2SO4D) CH3Cl

AlCl3m-Nitrotoluene

E) All of these are equally good. Ans: C

Topic: Synthesis

38. Starting with benzene, the best method for preparing p-nitrobenzoic acid is: A) HNO3/H2SO4; then CH3Cl/AlCl3; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+. B) CH3Cl/AlCl3; then HNO3/H2SO4; then separation of isomers; then KMnO4/

-OH/heat, followed by H3O+. C) CH3Cl/AlCl3; then KMnO4/-OH/heat, followed by H3O+; then HNO3/H2SO4. D) HNO3/H2SO4; then KMnO4/-OH/heat, followed by H3O+; then CH3Cl/AlCl3. E) HNO3/H2SO4; then CO2, followed by H3O+. Ans: B

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Topic: Synthesis

39. A good synthesis of

(CH3)3C CCH3

O

would be: A)

BenzeneCH3CCl

O

AlCl3

(CH3)3CCl

AlCl3B)

BenzeneCH3CCl

O

AlCl3

(CH3)3CCl

AlCl3C)

BenzeneCH3CCl

O

AlCl3 HF

(CH3)2C CH2

D) More than one of these E) None of these Ans: B

Topic: Synthesis

40. Which would be a good synthesis of m-nitrobenzoic acid? A)

BenzeneHNO3/H2SO4

heat AlCl3

CH3Cl 1. KMnO4, NaOH, heat

2. H3O+

B) Toluene

HNO3/H2SO4

heat

1. KMnO4, NaOH, heat

2. H3O+

C) Toluene

HNO3/H2SO4

heat

1. KMnO4, NaOH, heat

2. H3O+

D) More than one of the above E) None of the above Ans: C

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Topic: Synthesis

41. Benzoic acid can be prepared by the oxidation of all of the following compounds except this one: A) C6H5CH=CH2 B) C6H5C≡CH C) C6H5COCH3 D) C6H5CH2CH2CH3 E) C6H5C(CH3)3 Ans: E

Topic: Synthesis

42. Which of the following reactions would yield isopropylbenzene as the major product? A)

BenzeneH2SO4

CH3CH CH2

B)

BenzeneH2SO4

CH3CHCH3

OH

C)

BenzeneAlCl3

CH3CHCH3

Cl

D) Benzene

AlCl3

CH3CH2CH2Cl

E) All of these Ans: E

Topic: Synthesis

43. Which of the following reactions could be used to synthesize tert-butylbenzene? A) H2SO4

C6H6 + CH2=C(CH3)2B) H2SO4

C6H6 + (CH3)3COHC) AlCl3

C6H6 + (CH3)3CClD) All of the above E) None of the above Ans: D

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Topic: Synthesis

44. Which of these is a satisfactory synthesis of 1-chloro-2-phenylethane? A) C6H5CH2CH3 + Cl2, Fe ⎯⎯→ B) C6H5CH2CH3 + Cl2, 400°C ⎯⎯→ C) C6H5CH2CH2OH + SOCl2 ⎯⎯→ D) C6H5CH=CH2 + HCl, peroxide ⎯⎯→ E) C6H6 + CH3CH2Cl, AlCl3 ⎯⎯→ Ans: C

Topic: Synthesis

45. Which of the following reactions would produce isopropylbenzene? A) Cl

AlCl3Benzene

B) Benzene

HFC) OH

H2SO4Benzene

D) Br

AlCl3Benzene

E) All of these Ans: E

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Topic: Synthesis

46. How might the following synthesis be carried out:

Benzene

CH2CH3

Cl

severalsteps

?

A) CH3CH2ClC6H6

AlCl3

Cl2FeCl3

product

B) CH3CH2ClC6H6

AlCl3

Cl2FeCl3

product

C)

C6H6AlCl3

Cl2FeCl3

productCH3CCl

O

Zn(Hg)

HCl

D)

C6H6AlCl3

Cl2FeCl3

productCH3CCl

O

Zn(Hg)

HCl

E) None of these syntheses is satisfactory. Ans: C

Topic: Synthesis

47. Which is the best sequence of reactions for the preparation of p-bromostyrene from ethylbenzene? A) Br2

Feproductethylbenzene

NBS, hν

CCl4

KOH

CH3CH2OHB) Br2

Feproductethylbenzene

NBS, hν

CCl4

KOH

CH3CH2OHC) Br2

Feproductethylbenzene

NBS, hν

CCl4

KOH

CH3CH2OHD) Br2

Feproductethylbenzene

630 oC

ZnO

E) None of these syntheses is satisfactory. Ans: B

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Topic: Synthesis

48. Which is the best sequence of reactions for the following transformation?

O

NO2

A) i) HNO3, H2SO4; ii) CH3MgBr, Et2O; iii) H3O+, heat B) i) CH3MgBr, Et2O; ii) H3O+, heat; iii) HNO3, H2SO4 C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat D) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) H3O+, heat E) None of these syntheses is satisfactory. Ans: A

Topic: Synthesis

49. Which is the best sequence of reactions for the following transformation?

OCH3

O

NO2

OH

A) i) HNO3, H2SO4; ii) 2EtMgBr, Et2O; iii) NH4Cl B) i) 2EtMgBr, Et2O; ii) H3O+; iii) HNO3, H2SO4 C) i) HNO3, H2SO4; ii) NaBH4, H2O; iii) 2EtMgBr, Et2O D) i) LAH; ii) 2EtLi, Et2O; iii) HNO3, H2SO4, heat E) None of these syntheses is satisfactory. Ans: A

Topic: Synthesis

50. Which is the best sequence of reactions for the following transformation?

OH

O

NO2

A) i) SOCl2; ii) C6H6, AlCl3; iii) Zn(Hg),HCl; iv) HNO3, H2SO4 B) i) SOCl2; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) H2, Ni C) i) HNO3, H2SO4; ii) SOCl2; iii) C6H6, AlCl3; iv) Zn(Hg),HCl D) i) PBr3; ii) HNO3, H2SO4; iii) C6H6, AlCl3; iv) NaBH4, H2O E) two of these syntheses are satisfactory. Ans: C

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Topic: Relative Reactivities

51. Which of the following compounds would be most reactive toward electrophilic substitution?

OH CH3 Br CHO NO2

I II III IV V A) I B) II C) III D) IV E) V Ans: A

Topic: Relative Reactivities

52. Which of the following compounds would be most reactive to ring bromination? CH3 NO2 CF3 Cl NH2

I II III IV V A) I B) II C) III D) IV E) V Ans: E

Topic: Relative Reactivities

53. Which of the following compounds would you expect to be most reactive toward ring nitration? A) Benzene B) Toluene C) m-Xylene D) p-Xylene E) Benzoic acid Ans: C

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Topic: Relative Reactivities

54. Which of the following compounds would be least reactive toward electrophilic substitution?

NO2

NO2

O NH

O

I II III IV V A) I B) II C) III D) IV E) V Ans: B

Topic: Relative Reactivities

55. Which of the following compounds would be most reactive toward ring nitration?

O

O

CF3 OH NH

O

I II III IV V A) I B) II C) III D) IV E) V Ans: D

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56. Which of the compounds listed below would you expect to give the greatest amount of meta-product when subjected to ring bromination?

OH HO O NH2 OCH3 CH3

I II III IV V A) I B) II C) III D) IV E) V Ans: B

Topic: Relative Reactivities

57. Which of the following compounds would be most reactive toward ring bromination?

O

OHO O NH2 OCH3

O

O O

I II III IV V A) I B) II C) III D) IV E) V Ans: C

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Topic: Relative Reactivities

58. Which of the compounds listed below would you expect to give the greatest amount of meta-product when subjected to ring nitration?

O NHO OCH3 CH3

I II III IV V A) I B) II C) III D) IV E) V Ans: B

Topic: Mechanisms and Intermediates

59. Which of the following structures contribute(s) to the resonance hybrid of the intermediate formed when bromobenzene undergoes para-chlorination?

Br

H Cl

Br

H Cl

Br

H Cl

Br

H ClI II III IV

++ +

.. .. .. ..: : : : : : :+

A) I B) II C) III D) IV E) All of the above Ans: E

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Topic: Mechanisms and Intermediates

60. Which of the following contributors to the resonance stabilized hybrid formed when aniline undergoes para-chlorination would be exceptionally stable?

NH2

H Cl

NH2

H Cl

NH2

H Cl

NH2

H ClI II III IV

++ +

: : :+

A) I B) II C) III D) IV E) None of these Ans: B

Topic: Mechanisms and Intermediates

61. Consider the structures given below. Which of them would be a relatively stable contributor to the hybrid formed when toluene undergoes para bromination?

CH3

BrII

CH3

H BrIII

+CH3

H BrIV

+

CH3

BrIV

++

CH3

H BrI

+

A) I B) II C) III D) IV E) V Ans: C

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Topic: Mechanisms and Intermediates

62. Which of the following structures does not contribute to the resonance hybrid of the intermediate formed when nitrobenzene undergoes meta-chlorination?

N N N

I II III

O O O OO O

ClH

ClH

ClH

+

+ +

::: : : ::::.. .. .. .. .. ..

A) I B) II C) III D) None of these contribute E) All of these contribute. Ans: E

Topic: Mechanisms and Intermediates

63. Which of these is the rate-determining step in the nitration of benzene? A) Protonation of nitric acid by sulfuric acid B) Protonation of sulfuric acid by nitric acid C) Loss of a water molecule by the protonated species to produce the nitronium ion D) Addition of nitronium to benzene to produce the arenium ion E) Loss of a proton by arenium ion to form nitrobenzene Ans: D

Topic: Directing Effects

64. The ortho/para product ratio is expected to be the smallest for the bromination of which of these? A) Toluene B) Isopropylbenzene C) Butylbenzene D) sec-Butylbenzene E) tert-Butylbenzene Ans: E

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Topic: Directing Effects

65. Which of the following is not a meta-directing substituent when present on the benzene ring? A) -NHCOCH3 B) -NO2 C) -N(CH3)3

+ D) -C≡N E) -CO2H Ans: A

Topic: Directing Effects

66. Each of the five disubstituted benzenes shown below is nitrated. In which of these cases does the arrow not indicate the chief position of nitration.

Cl

OH

COOH Cl NHCOCH3

CH3

CCH3

CH2CH3

NO2

Cl

O

I II III IV V

A) I B) II C) III D) IV E) V Ans: C

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Topic: Directing Effects

67. Which of the following compounds would yield the greatest amount of meta product when subjected to ring nitration?

I II III IV V

HO O OH

O

O

HO

OHO

HO O

A) I B) II C) III D) IV E) V Ans: A

Topic: Directing Effects

68. Which of the following is not an ortho-para director in electrophilic aromatic substitution? A) -CF3 B) -OCH3 C) -CH3 D) -F E) -NH2 Ans: A

Topic: Directing Effects

69. Which of these compounds gives essentially a single product on electrophilic substitution of a third group? A) p-chlorotoluene B) m-ethylanisole C) 1-bromo-2-chlorobenzene D) m-xylene E) 3-hydroxybenzoic acid Ans: D

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Topic: Directing Effects

70. What is a feature found in all ortho-para directing groups? A) An oxygen atom is directly attached to the aromatic ring. B) The atom attached to the aromatic ring possesses an unshared pair of electrons. C) The group has the ability to delocalize the positive charge of the arenium ion. D) The atom directly attached to the aromatic ring is more electronegative than

carbon. E) The group contains a multiple bond. Ans: C

Topic: Directing Effects

71. Which is the best prediction of the site(s) of substitution when 3-methylphenol is nitrated? A) C-2 B) C-4 C) C-5 D) C-6 E) C-4 and C-6 Ans: E

Topic: Directing Effects

72. (Trifluoromethyl)benzene, C6H5CF3, will A) nitrate rapidly in the ortho-para positions. B) nitrate slowly in the ortho-para positions. C) nitrate rapidly in the meta position. D) nitrate slowly in the meta position. E) fail to nitrate under any conditions. Ans: D

Topic: Directing Effects

73. What feature is common to all meta-directing groups? A) The atom directly attached to the ring has a full or well-developed partial positive

charge. B) The atom directly attached to the ring is doubly bonded to oxygen. C) One or more halogen atoms are present in the group. D) One or more oxygen atoms are present in the group. E) The group is attached to the ring through a carbon atom. Ans: A

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Topic: Directing Effects

74. Arrange the following compounds in order of decreasing reactivity in electrophilic substitution:

O O Br NO2

I II III IV V A) V > II > I > III > IV B) II > V > III > I > IV C) IV > I > III > V > II D) III > II > I > IV > V E) IV > V > II > I > III Ans: B

Topic: Other EAS Considerations

75. Which of these liquids would be unsuitable as an inert solvent for a Friedel-Crafts reaction? A) Chlorobenzene B) Nitrobenzene C) Acetophenone D) (Trifluoromethyl)benzene E) All could be used. Ans: A

Topic: Other EAS Considerations

76. Undesired polysubstitution of an aromatic nucleus is most likely to be encountered in the case of: A) Friedel-Crafts alkylation B) Friedel-Crafts acylation C) Nitration D) Sulfonation E) Chlorination Ans: A

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Topic: Other EAS Considerations

77. This molecule cannot participate as a reactant in a Friedel-Crafts reaction. A) Benzene B) Chlorobenzene C) Nitrobenzene D) Toluene E) tert-Butylbenzene Ans: C

Topic: Other EAS Considerations

78. Which one of these molecules can be a reactant in a Friedel-Crafts reaction? A) Aniline B) Nitrobenzene C) Chloroethene D) Bromobenzene E) p-Bromonitrobenzene Ans: D

Topic: Other EAS Considerations

79. This substituent deactivates the benzene ring towards electrophilic substitution but directs the incoming group chiefly to the ortho and para positions. A) -OCH2CH3 B) -NO2 C) -F D) -CF3 E) -NHCOCH3 Ans: C

Topic: Other EAS Considerations

80. In electrophilic aromatic substitution, the attacking species (the electrophile) necessarily is a: A) Neutral species. B) Positively charged species. C) Lewis acid. D) Proton. E) Carbocation. Ans: C

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Topic: Other EAS Considerations

81. The electrophilic bromination or chlorination of benzene requires, in addition to the halogen: A) Hydroxide ion. B) A Lewis base. C) A Lewis acid. D) Peroxide. E) Ultraviolet light. Ans: C

Topic: Non-EAS Reactions

82. What is the Birch reduction product of the following reaction?

I II III IV V

Na, NH3(l)EtOH ?

A) I B) II C) III D) IV E) V Ans: D

Topic: Non-EAS Reactions

83. SN1 solvolysis of C6H5CH=CHCH2Cl in water produces: A) C6H5CH2C(OH)=CH2 B) C6H5CH=CHCH2OH C) C6H5CHOHCH=CH2 D) A mixture of B) and C) E) A mixture of A), B) and C) Ans: D

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Topic: Non-EAS Reactions

84. Which compound is capable of undergoing both SN1 and SN2 reactions in ordinary nonacidic solvents?

Br

Br

Br

Br Br

I II III IV VA) I B) II C) III D) IV E) V Ans: D

Topic: Non-EAS Reactions

85. Which alkyl halide can undergo both SN1 and SN2 reactions in nonacidic solvents? A) CH3Br B) CH3CH2CH2Br C) CH2 CHCHCH3

Br

D) C6H5CH2CH2CH2Br E)

C6H5CCH2Br

CH3

CH3

Ans: C

Topic: Non-EAS Relative Rates and Intermediates

86. The rate of solvolysis in ethanol is least for which of these compounds? A) C6H5CH2Cl B) C6H5C(CH3)2

Cl

C) (C6H5)2CHCl D) C6H5CHCl

CH3

E) (C6H5)3CCl Ans: A

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Topic: Non-EAS Relative Rates and Intermediates

87. Which of the following structures would not be a contributor to the resonance hybrid of the benzyl cation?

CH3

II

CH2

III

CH2

IV

CH3

IV

+

+

CH3

I

+

H+

+H

A) I B) II C) III D) IV E) V Ans: A

Topic: Non-EAS Relative Rates and Intermediates

88. Which of these species is/are proposed as intermediate(s) in the mechanism for the Birch reduction? A) Radical B) Carbanion C) Radical anion D) Both A) and B) E) All of A), B) and C) Ans: E

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Topic: Non-EAS Relative Rates and Intermediates

89. Which of the following carbocations would be most stable? A)

C6H5CH2CH2CHCH2

CH3

B)

C6H5CH2CH2CHCH3

CH2

C)

C6H5CH2CH2CCH3

CH3

D)

C6H5CH2CHCHCH3

CH3

E) C6H5CHCH2CHCH3

CH3

Ans: E

Topic: Non-EAS Relative Rates and Intermediates

90. Which alkyl halide would be most reactive in an SN2 reaction? A) C6H5CH2CH2CH2Br B) C6H5CHCH2Br

CH3

C) C6H5CH2CHCH3

Br

D)

C6H5CCH2Br

CH3

CH3

E) C6H5CCH3

Br

CH3

Ans: A

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Topic: Non-EAS Relative Rates and Intermediates

91. Which alkyl halide would be most reactive in an SN1 reaction? A) C6H5CH2CH2CH2Br B) C6H5CH2CHCH3

Br

C)

C6H5CH2CBr

CH3

CH3

D) C6H5CCH3

Br

CH3

E) C6H5CCH2Br

CH3

CH3

Ans: D SHORT ANSWER QUESTIONS Topic: General

92. Aromatic hydrocarbons are generally known as ____________. Ans: arenes

Topic: General Reactivity

93. Benzene is susceptible to electrophilic attack primarily because of its _____________. Ans: exposed π system

Topic: General Reactivity

94. Although benzene is susceptible to electrophilic attack, its special stability causes it to undergo ______________ rather than ____________ reactions. Ans: substitution; addition

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Topic: EAS Mechanism

95. In general, there are three steps to an electrophilic aromatic substitution reaction. These are: a) formation of an _____________; b) reaction with an aromatic ring to form an ___________; and c) loss of a _________ to reform the aromatic system. Ans: electrophile; arenium ion; proton

Topic: General Reactivity

96. Aryl and vinyl halides cannot be used in the Friedel-Crafts alkylation because they do not __________. Ans: form carbocations readily

Topic: General EAS Reactivity

97. Substituent groups affect both _____________ and _______________ in electrophilic aromatic substitution reactions. Ans: reactivity; orientation

Topic: General EAS Reactivity

98. Electron-donating groups increase the electron density on the aromatic ring, causing it to be more reactive than benzene itself towards EAS. These types of groups are called _____________ groups. Ans: activating

Topic: General EAS Reactivity

99. Electron-withdrawing groups decrease the electron density on the aromatic ring, causing it to be less reactive than benzene itself towards EAS. These types of groups are called _____________ groups. Ans: deactivating

Topic: General EAS Reactivity

100. With the exception of halogens, activating groups are ____________ directors and deactivating groups are _________ directors. Ans: ortho/para; meta

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Topic: General EAS Reactivity

101. When two different groups are present on a benzene ring, the ____________ generally determines the outcome of an EAS reaction. Ans: more powerful activating group

Topic: EAS/non-EAS Reactivity

102. When toluene reacts with Cl2, the identity of the major product(s) obtained depends on whether the reaction is carried out in the presence of catalytic amounts of FeCl3, or without catalyst, at high temp. Explain clearly. Ans: Reaction with Cl2/FeCl3 results in electrophilic aromatic substitution at the o- and

p- positions, since the methyl group in toluene is an activating, o-,p- director. In contrast, when the reaction is carried out without catalyst, at high temperature, the methyl group undergoes free-radical halogenation via the benzyl radical intermediate.

Cl

ClCl

Cl2FeCl3

Cl2heat

+

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Topic: General EAS Reactivity

103. When the following substance is treated with Br2/FeBr3, the major product is obtained in good yield, and only very small amounts of minor products are found. What is this major product and why are the minor products not formed to any significant degree? Explain clearly.

HN

O

O

Br2FeBr3

?

Ans: The major products are produced by brominating Ring B. Ring B is more electron-rich due to the electron-donation of both the nitrogen and methyl groups attached versus the two electron-withdrawing carbonyl groups attached to Ring A, which make it inherently electron-poor. Therefore, bromination mainly occurs on the more electron-rich benzene ring affording a mixture of the following two compounds. Due to steric effects, bromination ortho to both the nitrogen and methyl group would lead to a minor product. Also, because Ring A is electron-poor, bromination of this ring would also lead to minor products.

HN

O

OBr

RingA

RingB

major productsHN

O

O

RingA

RingB

Br

+

Topic: Synthetic Strategy

104. Suggest a reasonable synthetic strategy for the synthesis of 3,5-dinitrobenzyl alcohol from benzaldehyde. Ans:

O OO2N

NO2

OHO2N

NO2HNO3 (excess)H2SO4heat

benzaldehyde 3,5-dinitrobenzyl alcohol

NaBH4 H2O

Topic: Synthetic Strategy

105. Suggest a reasonable synthetic strategy for the synthesis of 4-methyl-1-phenyl-1-pentanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COCl Ans: O OH

Cl

O AlCl3

4-methylpentanoyl chloride 4-methyl-1-phenyl-1-pentanol

NaBH4 H2O

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Topic: Synthetic Strategy

106. Suggest a reasonable synthetic strategy for the synthesis of 6-methyl-3-phenyl-3-heptanol from 4-methylpentanoyl chloride, (CH3)2CHCH2CH2COCl Ans: O OH

Cl

Oi) C2H5MgBrii) NH4ClAlCl3

4-methylpentanoyl chloride 6-methyl-3-phenyl-3-heptanol Topic: Mechanism, Carbocation Stability

107. Acid-catalyzed hydration of 1-phenyl-1-pentene gives 1-phenyl-1-pentanol almost exclusively; the other possible hydration product, 1-phenyl-2-pentanol, is not detected at all. Explain clearly. Ans: Acid catalyzed hydration of an alkene occurs through a carbocation intermediate.

Although 1-phenyl-1-pentene is symmetrically substituted at the C=C, the relative stabilities of the two possible carbocation intermediates is significantly different: although both are secondary carbocations, one is also benzylic and thus stabilized by resonance. The observation that 1-phenyl-1-pentene gives 1-phenyl-1-pentanol, almost exclusively, is in accordance with the general trend that acid catalyzed hydration chiefly tends to afford products formed via the most stable intermediate carbocation.

H3O+

H2O

H

OH

H

H

OH

H++

2o, benzylic:stabilized by resonance,formed almost exclusively

2o, but not benzylic:less stable, not formed to any appreciable degree

+

+

chief product not detected

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Topic: Spectroscopic Analysis

108. How might 1H NMR spectroscopy be useful in distinguishing between the following two substances?

OOO

O

BA Ans: The chemical shift of the methyl protons is likely to be markedly different in the

two substances. In A, the signal may be expected at about 3.5-4.0 ppm (attachment to O), while in B, it is likely to show up at about 2.0 ppm (attachment to >C=O).

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MULTIPLE CHOICE QUESTIONS

Topic: Nomenclature

1. What is the correct IUPAC name for the following compound?

O A) 2-Methyl-5-heptanone B) 7-Methyl-4-octanone C) 6-Isopropyl-4-octanone D) Isobutyl propyl ketone E) 1,1-Dimethyl-4-heptanone Ans: B

Topic: Nomenclature

2. What is the correct IUPAC name for the following compound?

O A) 5,5-Dimethyl-2-heptanone B) 5-Ethyl-5,5-dimethyl-Methyl-2-octanone C) 5-Ethyl-5-methyl- 2-hexanone D) 5,5-Dimethyl-2-octanone E) 3,3-Dimethyl-6-heptanone Ans: A

Topic: Nomenclature

3. What is the correct IUPAC name for the following compound?

O A) 1,1,2-Trimethyl-1,3-hexenone B) 1,2-Dimethyl-1,3-hexenone C) 2,3-Dimethyl-1,3-heptenone D) 2,3-Dimethyl-2-hepten-4-one E) 5,6-Dimethyl-5-hepten-4-one Ans: C

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Topic: Nomenclature

4.

A correct name for C6H5CH2CH2CH

O

is? A) 3-Benzylpropanone B) 3-Phenylpropanal C) 3-Benzylpropanal D) Nonanone E) Nonanal Ans: B

Topic: Nomenclature

5. A correct name for the following compound would be which of those below?

H

O

A) 2,5-Dimethyl-6-hexanal B) 2,5-Dimethylhexanal C) 2-Aldehydoisohexane D) 3,5-Dimethylheptanone E) 1-Hydro-2,5-dimethyl-1-hexanone Ans: B

Topic: Nomenclature

6.

What is the IUPAC name for

CH3 CH

OH

CH2 C CH

O

C6H5

CH3

? A) 4-Oxo-5-phenyl-2-hexanol B) 5-Hydroxy-2-phenyl-3-hexanone C) 2-Hydroxy-5-phenyl-4-hexanone D) 2-Hydroxypropyl-1-phenylethyl ketone E) 5-Hydroxy-3-keto-2-phenylhexane Ans: B

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Topic: Nomenclature

7. Which is the proper name for the structure shown?

CHO

CH3

Cl

A) 2-Chloro-5-aldehydotoluene B) 6-Chloro-3-aldehydotoluene C) 2-Methyl-4-aldehydochlorobenzene D) 4-Chloro-3-methylbenzaldehyde E) 4-Methyl-5-chloro-2-benzaldehyde Ans: D

Topic: Nomenclature

8. Which is the proper name for the structure shown?

O2N

NO2

O

A) 3-Methyl-5-(1,4-dinitrobenzyl)-1-pentanal B) 3-Methyl-1-(2,5-dinitrophenyl)-5-pentanal C) 3-Methyl-5-(2,5-dinitrophenyl)pentanal D) 3-Methyl-5-(2,5-dinitrophenyl)pentanaldehyde E) 3-Methyl-5-(2,5-dinitrophenyl)pentaldehyde Ans: C

Topic: Nomenclature

9. Which is the proper name for the structure shown?

O

Cl A) 3,5-Dimethyl-5-(4-chlorobenzyl)-1-pentanal B) 3-Methyl-5-(4-chlorophenyl)hexanol C) 3,5-Dimethyl-5-(4-chlorophenyl)-1-pentanaldehyde D) 3-Methyl-5-(4-chlorophenyl)-hexanaldehyde E) 3-Methyl-5-(4-chlorophenyl)hexanal Ans: E

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Topic: Nomenclature

10. Which is the proper name for the structure shown below?

BrO

A) 7-Bromo-1,4-octynal B) 7-Bromo-1,4-octynone C) 2-Bromo-5,7-octynal D) 7-Bromo-7-methyl-1-heptyne-3-ketone E) 7-Bromo-1-octyn-4-one Ans: E

Topic: Nomenclature

11. Which is the IUPAC name for the structure shown below?

O

Br H

A) (R)-5-Bromo-2-heptanal B) (S)-5-Bromo-2-heptanal C) (R)-5-Bromo-2-heptanone D) (S)-5-Bromo-2-heptanone E) (R)-3-Bromopentyl methyl ketone Ans: C

Topic: Nomenclature

12. Which is the IUPAC name for the structure shown below?

O A) 5-Cyclohexyl-2-hexanal B) 5-Cyclohexyl-2-hexanone C) 5-Cyclohexyl-5-methyl-2-pentanone D) 5-(1-Methylcyclohexyl)-2-pentanone E) 4-(1-Methylcyclohexyl)-2-butanone Ans: E

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Topic: New Functional Groups

13. Which of the following compounds is an acetal?

I

OCH3

O O

II

O OH

O

III

O

O

IV

O O

A) I B) II C) III D) IV E) None of these Ans: C

Topic: New Functional Groups

14. Which is the general formula for a thioacetal? A)

RC S

H

B) RCHSR'

OH

C) RCHSR'

SH

D) RCHSR'

SR'

E) RCHOR'

SR'

Ans: D

Topic: New Functional Groups

15. Which compound is an acetal?

I

O OH

III

O

O

IV

O OH

II

O OCH3

A) I B) II C) III D) IV E) All of the above Ans: B

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Topic: Reaction Products

16. The product, C, of the following reaction sequence,

CH3CCH3

O

CN+HCN

C4H7NOH2O

H2SO4heat

C

would be: A)

CH2 CCOOH

CH3

B) CH3CH2COOCH3 C) CH3CHCH3

CN

D) CH3CH=CHCOOH E) None of these Ans: A

Topic: Reaction Products

17. The product, H, of the following reaction sequence,

FC6H5Li

etherGC6H5CH2Br + (C6H5)3P

C6H5CCH3

O

H

would be: A)

C6H5CH2CC6H5

CH3

OH

B)

C6H5CH2CC6H5

O

C) C6H5CH CHCC6H5

O

D) C6H5CH2CH=CHC6H5 E) C6H5CH CCH3

C6H5

Ans: E

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Topic: Reaction Products

18. What would be the product of the following reaction sequence?

IV

OH

O

I II

V

III

OH

OO OH

i) PCl3ii) C6H6, AlCl3iii) Zn(Hg), HCl, heat

?

A) I B) II C) III D) IV E) V Ans: E

Topic: Reaction Products

19. What new compound will be formed when HCl is added to a solution of pentanal in methanol? A) O

O B) O

Cl C) OH

OH D) O

O E) Cl

O Ans: A

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Topic: Reaction Products

20. What would be the product of the following reaction sequence?

IV

OH

O

I II

V

IIIOH

O OH

i) PCl3ii) C6H6, AlCl3iii) NaBH4, H2O

?

OH

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products

21. The product, K, of the following sequence of reactions

ICH3CH2MgBr

etherJBenzene

CH3CHCOClK

CH3

AlCl3

H3O+

would be:

OH HO

O

OH O

I II III IV VA) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

22. Dissolving benzaldehyde in methyl alcohol establishes an equilibrium with what compound? A)

C6H5CHOCH3

OH

B)

C6H5COCH3

O

C) C6H5C(OCH3)3 D) Answers A) and B) E) Answers B) and C) Ans: A

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Topic: Reaction Products

23. Predict the major organic product of the following reaction:

O

H

HO2C O

O

H3C O

O

H3C

O

OH3C

OHO

H

O

H

I II III IV V

Ag(NH3)2+

H2O?

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

24. The product, E, of the following reaction sequence,

CH3CH2COOHPCl5 C6H6

AlCl3

NaBH4

CH3OHC D E

would be:

CH2CH2CH3 COCH2CH3

O

CCH2CH3

O

CHCH2CH3

OH

CH(CH3)2

I II III IV VA) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

25. Select the structure of the major product in the following reaction.

?i) BH3

ii) H2O2,OH-, H2O A) Ethylbenzene B) 1-Phenylethanol C) Acetophenone D) 2-Phenylethanal E) Vinylbenzene Ans: D

Topic: Reaction Products

26. Select the structure of the major product in the following reaction.

?H2SO4 HgSO4, H2O

A) Ethylbenzene B) 1-Phenylethanol C) Acetophenone D) 2-Phenylethanal E) Vinylbenzene Ans: C

Topic: Reaction Products

27. Select the structure of the major product in the following reaction.

?i) H2, Lindlar catalystii) O3iii)Zn, CH3CO2H

A) 4-methylhexanal B) 4-methyl-1-hexanol C) 3-methylhexanal D) 4,10-dimethyldodecane-6,7-dione E) 4,10-dimethyldodecane-6,7-diol Ans: A

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Topic: Reaction Products

28. The product, J, of the following reaction sequence, CH3CHCOOH

CH3

SOCl2 I(CH3)2CuLi

etherJ

would be: A)

CH3CHCOCH3

CH3

O

B) CH3C

CH3

OH

CCH3

O

C) CH3CHCOCu

CH3

D) CH3CHCCH3

CH3

O

E) CH3CHCCHCH3

CH3

O

CH3

Ans: D

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Topic: Reaction Products

29. What is the major product of the following reaction sequence?

O

NOSO3H COHO

CN OSO3H

CN

CNH2

H

HCN H2SO4

H2Oheat

I II III IV V

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reaction Products

30. The product, D, of the following sequence of reactions

CH3CH2COH

O SOCl2A

tolueneAlCl3

BZn(Hg)

HClD

+

C (discard)

would be:

CH3 CH2CH2CH3 CH3CH2CCH2

O

CH3 CH2CH2CCl

O

CH3 CH2CH2CH2Cl CH3 CHCH3

CH3

I II III

IV VA) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

31. What new compound will be formed when gaseous HCl is added to a solution of propanal in methanol? A)

CH3CH2COCH3

O

B) CH3CH2COH

O

C) CH3CH2CH(OCH3)2 D) CH3CH2CHOCH3

OH

E) None of the above Ans: C

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Topic: Reaction Products

32. What is the product of the following reaction sequence?

C6H5CH2OH

PCC

CH2Cl2

BrCH2CO2Et, Zn

benzene

H3O+

A) C6H5CH2OCH2CO2Et B)

C6H5COCH2CO2Et

O

C)

C6H5CHCH2CO2Et

OH

D)

C6H5CHOCH2CO2Et

OH

E) C6H5CH2CH2CO2Et Ans: C

Topic: Reaction Products

33. What would be the final product?

C6H5CCH3

O

CH3I(C6H5)3P

ether

C6H5Li?

A) C6H5C CH2

CH3

B)

C6H5CCH3

C6H5

CH3

C) C6H5CH=CHCH3 D)

C6H5CCH3

OH

CH3

E) C6H5CH CC6H5

CH3

Ans: A

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Topic: Reaction Products

34. What is the major product of the following reaction sequence? OCH3

OO

I II III

OH

HO HO

O OH

OO

IV V

i)

ii) LAH, Et2O

iii) H2O, H3O+

?

OH

O

OH

O

HOOH, HCl

A) I B) II C) III D) IV E) V Ans: E

Topic: Reaction Products

35. An aldehyde results from the reaction of which of these compounds with aqueous base? A) CH3CH2CH2Cl B) CH3CHClCH2Cl C) CH3CH=CCl2 D) CH3CH2CHCl2 E) CH3CCl2CH3 Ans: D

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Topic: Reaction Products

36. The Baeyer-Villiger oxidation of propiophenone (ethyl phenyl ketone) produces chiefly:A)

CH3CH2OCC6H5

O

B) CH3CH2OCOC6H5

O

C) p-HOC6H4CCH2CH3

O

D) C6H5OCCH2CH3

O

E) C6H5CCH2CH2OH

O

Ans: D

Topic: Reaction Products

37. What is compound V in the following synthesis?

O

Cl+ V

1. ether

2. H3O+

O

(C6H5)3P + WC6H5Li

etherWittigreagent

A) CH3CH2COCl B) CH3CH2MgBr C) CH3COCl D) (CH3)2CuLi E) (CH3CH2)2CuLi Ans: E

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Topic: Reaction Products

38. What is the reactant W in the synthesis given below? O

Cl+ V

1. ether

2. H3O+

O

(C6H5)3P + WC6H5Li

etherWittigreagent

A) Cyclopentanone B) Cyclopentene C) Cyclopentanol D) Bromocyclopentane E) Triphenylphosphine oxide Ans: D

Topic: Reaction Products

39. What is the final product, Z, of the following synthesis?

CH3

COAl(t-Bu)2

O

COCH3

O

CH

O

COLi

O

COH

O

1. KMnO4, OH-, heat2. H3O+

SOCl21. LiAlH(O-t-Bu)3 ether, -78 oC2. H2O

X Y Z

I II III IV VA) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

40. What is the final product of this synthetic sequence?

Benzene

Br2

FeCl3

Mg

ether

1. C6H5CHO

2. H3O+

H2Cr2O4

acetone?

A)

C6H5CC6H5

O

B) p-BrC6H4CH2C6H5 C) C6H5CH2COOH D)

C6H5CH2CC6H5

O

E) C6H5CH2C6H5 Ans: A

Topic: Reaction Products

41. The reaction of tert-butyl methyl ketone with a peroxy acid produces which of these as the principal product(s)? A)

(CH3)3COCCH3

O

B)

(CH3)3CCOCH3

O

C)

(CH3)2C

O

COCH3

CH3

D) (CH3)3COH + HO2CCH3 E)

(CH3)3COCOCH3

O

Ans: A

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Topic: Synthesis

42. Which of the following reactions would yield benzaldehyde? A)

C6H5CH2ClOH-

H2Oheat

B) C6H5CH(OCH3)2

H3O+

C) C6H5COOH

1. LiAlH4, ether

2. H2OD) Answers A) and B) E) Answers A), B), and C) Ans: B

Topic: Synthesis

43. Which of the reactions listed below would serve as a synthesis of acetophenone,

C6H5CCH3

O

?

A)

C6H5CCl

O

+ (CH3)2CuLiB)

C6H6 + CH3COClAlCl3

C) C6H5CN + CH3Li

ether H3O+

D) Answers A) and B) only E) Answers A), B), and C) Ans: E

Topic: Synthesis

44. Which of the following would yield 3-pentanone as the major product? A)

CH3CH2CN + CH3CH2Liether H3O+

Product

B) CH3CH2CO2H + 2 CH3CH2Li

ether H3O+Product

C)

CH3CH2CCl + (CH3CH2)2CuLiether

O

D) Two of these E) All of these Ans: E

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Topic: Synthesis

45.

Which of the following procedures would not yield (CH3)2CHCH

O

as a product?

OH

CO2H

OH

O

O

PCC

CH2Cl2

SOCl2ether, -78 oC

O3 Zn

HOAc

KMnO4

NaOH

H3O+

H3O+

I

II

III

IV

V

LiAlH(O-t-Bu)3

A) I B) II C) III D) IV E) V Ans: D

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Topic: Synthesis

46. Which of the following procedures would not yield 3-pentanone as a major product? A) H3O+

CH3CH2CNCH3CH2MgBr

etherB)

H2O2 CH3CH2Li

etherCH3CH2COH

O

C) H3O+CH3CH2CN

CH3CH2Li

etherD)

(CH3CH2)2CuLi

etherCH3CH2CCl

O

E) H3O+CH3CH2CO2H

CH3CH2MgBr

etherAns: E

Topic: Synthesis

47. How could the following synthetic conversion be accomplished?

CH3CH2CCH3

O

CH3CH2CH2CHOA) HgSO4/H2SO4; then PCl5/0°C; then NaNH2, liq. NH3 B) PCl5/0°C; then NaNH2, liq. NH3; then Sia2BH; then H2O2 C) PCl5/0°C; then NaNH2, liq. NH3; then HgSO4, H2SO4/H2O D) NaNH2, liq. NH3; then PCl5/0°C; then HgSO4, H2SO4/H2O E) H2O2; then PCl5/0°C; then NaNH2, liq. NH3; then Sia2BH Ans: C

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Topic: Synthesis

48. Which sequence of reactions would be utilized to convert

O CO2CH3 O C

CH3CH3

OH

into ?

A) 2CH3MgBr, then NH4+

B) HOCH2CH2OH, H3O+; LiAlH4, ether; 2CH3MgBr, then NH4+

C) HOCH2CH2OH, H3O+; 2CH3MgBr, then NH4+

D) HOCH2CH2OH, H3O+; H2, Pt; CH3OH, NH4+

E) None of the above Ans: C

Topic: Synthesis

49. Which reaction sequence would be used to prepare

O

H

O

Cl

O

MgBr+1. ether

2. H3O+

H2

NiI

+ 2 CH3MgBr1. ether

2. H3O+

H2

NiII

III(C6H5)3P C6H5Li cyclopentanone H2

Ni

IVCH3MgBr

ether

H3O+

?

A) I B) II C) III D) IV E) All of the above would yield the product. Ans: C

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Topic: Synthesis

50. Which Wittig reagent would be used to synthesize

CH=P(C6H5)3 P(C6H5)3CH3CH=P(C6H5)3 CH3CH2CH=P(C6H5)3

I II III IV

?

A) I B) II C) III D) IV E) Either I or II could be used. Ans: E

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Topic: Synthesis

51. A good synthesis of

H

O

H

OH

H

H

H2O, H2SO4

HgSO4I

II1. Sia2BH

2. H2O2, NaOH

III1. O3

2. Zn, HOAc

1. KMnO4, NaOH, heat

2. H3O+IV

would be:

A) I B) II C) III D) IV E) All of these are equally useful. Ans: B

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Topic: Synthesis

52. Which of the following is not a synthesis of benzophenone,

C6H5CC6H5

O

?

A)

C6H5CCl

O

C6H6 +AlCl3

B) (C6H5)2CHOH

H2CrO4

acetoneC)

(C6H5)2CH=CH21. O3

2. Zn, HOAcD)

(C6H5)2CO2H + 2 C6H5Li1. ether

2. H2OE) All of the above will give benzophenone. Ans: E

Topic: Synthesis

53. Which of the following is a synthesis of 3-heptanone? A)

CH3CH2CH2CH2CH2OHPCC

CH2Cl2

1. CH3CH2MgBr

2. H3O+

H2Cr2O4

acetoneB)

CH3CH2CNCH3(CH2)2CH2Li H3O+

etherC)

CH3CH2CH2CH2OHPBr3 CH3CH2MgBrNaCN

ether

H3O+

etherD)

CH3CH2CH2CH2CH2OHKMnO4

OH-,

2 CH3CH2LiH3O+

ether

H2O

E) All of the above are syntheses of 3-heptanone. Ans: E

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Topic: Synthesis

54. Which synthesis or syntheses would yield propanal? A)

CH3CH2CH2OHPCC

CH2Cl2B)

CH3CH2CCl

OLiAlH[OC(CH3)3]3

ether, -78 oCC)

CH3C CH1. Sia2BH

2. H2O2, OH-

D) All of these E) None of these Ans: D

Topic: Reagents

55. LiAlH4 (LAH) cannot be used to convert carboxylic acids to the corresponding aldehydes because: A) LAH is not sufficiently reactive. B) RCOOH is converted into RCOOLi. C) RCOOH is reduced to RCH2OH. D) RCOOH is reduced to RCH3. E) RCOOH is converted into R2C=O. Ans: C

Topic: Reagents

56. The following reduction can be carried out with which reagent(s)?

O

?

A) Zn(Hg), HCl B) i) HSCH2CH2SH, BF3 ; ii)Raney Ni (H2) C) NaBH4, CH3OH D) A & B E) A & C Ans: D

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Topic: Reagents

57. Identify the reagent(s) that would bring about the following reaction: CH3CH2CH2COCl ⎯⎯⎯→ CH3CH2CH2CHO A) H2/Ni B) Li/liq.NH3 C) LiAlH[OC(CH3)3]3, ether D) NaBH4, CH3OH E) LiAlH4, ether Ans: C

Topic: Reagents

58. Which reagent will not differentiate between 3-butenal and 2-butanone? A) Br2/CCl4 B) Ag2O,OH- C) H2NNHC6H5 D) KMnO4,OH- E) None of these Ans: C

Topic: Reagents

59. The Reformatsky reaction involves the reaction of an aldehyde or ketone with: A) RLi B) R2CuLi C)

XZnCHCO2R'

R

D) RC≡CNa E) R3P Ans: C

Topic: Reagents

60. Acetals are unstable in the presence of an aqueous solution of which of these? A) HCl B) NaOH C) KHCO3 D) Na2CO3 E) NaCl Ans: A

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Topic: Reagents

61.

The compound C6H5C N N CC6H5

HH

is produced by the reaction of an excess of benzaldehyde with which compound? A) Ammonia B) Hydrazine C) Nitrogen D) Phenylhydrazine E) Hydroxylamine Ans: B

Topic: Reagents

62. Which of these will not catalyze the reaction of a weak nucleophile with the carbonyl group of an aldehyde or ketone? A) I- B) H3O+ C) AlCl3 D) BF3 E) ZnCl2 Ans: A

Topic: Reagents

63. Which reagent(s) could be used to carry out the following transformation?

O?

A) Zn(Hg), HCl, reflux B) LiAlH4, ether C) HSCH2CH2SH, BF3; then Raney Ni (H2) D) All of the above E) Two of the above Ans: E

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Topic: Physical Properties, Relationships, Stereochemistry

64. Which of the compounds listed below would you expect to have the highest boiling point? (They all have approximately the same molecular weight.) A) pentane B) 1-butanol C) Butanal D) 1-fluorobutane E) diethylether Ans: B

Topic: Physical Properties, Relationships, Stereochemistry

65. What is the order of decreasing reactivity of aldehydes, esters and ketones towards the organozinc compounds used in the Reformatsky reaction? A) Aldehydes > esters > ketones B) Esters > aldehydes > ketones C) Ketones > esters > aldehydes D) Ketones > aldehydes > esters E) Aldehydes > ketones > esters Ans: E

Topic: Physical Properties, Relationships, Stereochemistry

66. What, in general, is the order of decreasing reactivity of these carbonyl compounds towards nucleophilic reagents?

CH3CCH3 CH3C O (CH3)3CCCH3 HC O (CH3)3CCC(CH3)3

O H O OH

I II III IV VA) I > III > V > II > IV B) IV > II > I > III > V C) V > III > I > II > IV D) II > I > V > III > IV E) III > V > IV > II > I Ans: B

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Topic: Physical Properties, Relationships, Stereochemistry

67. Which of these gem-diols is expected to be the most stable? A)

CF3CCF3

OH

OH

B) CH3CH(OH)2 C)

CH3CCH3

OH

OH

D) C6H5CH(OH)2 E) ClCH2CH(OH)2 Ans: A

Topic: Physical Properties, Relationships, Stereochemistry

68. The relationship of 3-methyl-2-heptanone and 3-methyl-2-hepten-2-ol is designated by the term: A) Tautomers B) Conformational isomers C) Diastereomers D) Resonance structures E) Stereoisomers Ans: A

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Topic: Physical Properties, Relationships, Stereochemistry .

69. In which of the following reactions is the final product expected to be formed as a racemic mixture? A)

C6H5C O

H

C6H5MgBr +B)

CH3CCH3

O

HCN +

C) CH3CH2C O BrZnCH2COC2H5

H O

+D)

CH3C O

H

+ xs CH3OH + HClE)

CH3CHCH2COC2H5

CH3

O

+ (i-Bu)2AlH

Ans: C

Topic: Physical Properties, Relationships, Stereochemistry

70. Stereoisomers can exist in the case of which of the following? A) The hydrazone of butanone B) The oxime of acetone C) The phenylhydrazone of cyclohexanone D) The cyclic acetal formed from propanal and ethane-1,2-diol E) The imine of cyclopentanone Ans: A

Topic: Physical Properties, Relationships, Stereochemistry

71. Stereoisomers can exist in the case of which of the following? A) The hydrazone of acetophenone B) The oxime of 2-methylcyclopentanone C) The phenylhydrazone of 4-methylcyclohexanone D) The imine of cyclopentanone E) Two of the above Ans: B

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Topic: Reactions of Aldehydes and Ketones

72. Which of the following is formed when 3-methylcyclopentanone reacts with hydroxylamine?

N-NH-C6H5 N-NH2 N-OH

I II III

NNH

NH2

O

IV

NNH NO2

NO2

VA) I B) II C) III D) IV E) V Ans: C

Topic: Reactions of Aldehydes and Ketones

73. Which of the following is formed when 3-methylcyclopentanone reacts with semicarbazide?

N-NH-C6H5 N-NH2 N-OH

I II III

NNH

NH2

O

IV

NNH NO2

NO2

VA) I B) II C) III D) IV E) V Ans: D

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Topic: Reactions of Aldehydes and Ketones

74. Which of the following is formed when 4-methylpentanal reacts with phenylhydrazine?

N-NH-C6H5 N-C6H5 N-NH2

I II III

IV V

NNH

NH2

ON=N-C6H5

A) I B) II C) III D) IV E) V Ans: A

Topic: Reactions of Aldehydes and Ketones

75. Which of the following is formed when 2,2,3-trimethylcyclohexanone reacts with hydroxylamine?

N-NH-C6H5 N-NH2

II

N-OH

IIII

NNH

NH2

O

IV

NNH NO2

NO2

VA) I B) II C) III D) IV E) V Ans: C

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Topic: Reactions of Aldehydes and Ketones

76. Which of the following is formed when 2,2,3-trimethylcyclohexanone reacts with semicarbazide?

N-NH-C6H5 N-NH2

II

N-OH

IIII

NNH

NH2

O

IV

NNH NO2

NO2

VA) I B) II C) III D) IV E) V Ans: D

Topic: Reactions of Aldehydes and Ketones

77. Which of the following is formed when 2,2,3-trimethylcyclohexanone reacts with hydrazine?

N-NH-C6H5 N-NH2

II

N-OH

IIII

NNH

NH2

O

IV

NNH NO2

NO2

VA) I B) II C) III D) IV E) V Ans: B

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Topic: NMR

78. A compound with formula C5H10O gives two signals only, both singlets, in the 1H NMR spectrum. Which of these structures is a possible one for this compound? A)

CH3CH2CCH2CH3

O

B) (CH3)2CHCCH3

O

C) (CH3)3CC O

H

D) CH3CH2CHC O

H

CH3

E) (CH3)2CHCH2C O

H

Ans: C

Topic: NMR

79. The 1H NMR spectrum of a compound with formula C7H14O gives three signals. Which of these structures is a possible one for this compound? A) 2-heptanone B) 3-heptanone C) 2,4-dimethyl-3-pentanone D) 2,2-dimethyl-3-pentanone E) two of the above Ans: E

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Topic: NMR

80. The 13C NMR spectrum of a compound with formula C7H14O gives three signals. Which of these structures is a possible one for this compound? A) 2-heptanone B) 3-heptanone C) 2,2-dimethyl-3-pentanone D) 2,4-dimethyl-3-pentanone E) two of the above Ans: D

Topic: NMR

81. The 1H NMR spectrum of a compound with formula C7H14O gives a doublet at 9.2 ppm. Which of these structures is a possible one for this compound? A) 2-methyl-3-hexanone B) 2-methylhexanal C) 2,2 -dimethylpentanal D) 2,2-dimethyl-3-pentanone E) two of the above Ans: B

SHORT ANSWER QUESTIONS Topic: Relative Reactivity

82. Aldehydes are more reactive than ketones towards nucleophilic substitution because of both steric and electronic factors. Briefly explain. a. Steric reasons: ______________. b. Electronic reasons: __________. Ans: a. aldehydes have the small hydrogen substituent on one side, so less steric

crowding than ketones b. aldehydes have only one electron-releasing group to partly neutralize/stabilize the partial positive charge at the carbonyl carbon while ketones have two

Topic: General

83. A compound with an OH and OR group attached to the same carbon is known as a(n) _____________. Ans: hemiacetal

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Topic: General

84. A compound with two OH groups attached to the same carbon is known as a(n) _________. Ans: hydrate or gem-diol

Topic: General

85. A compound with two OR groups attached to the same carbon is known as a(n) _________. Ans: acetal

Topic: General

86. A compound containing a C=N double bond is known as a(n) __________. Ans: imine

Topic: General

87. A compound with an OH and CN group attached to the same carbon is known as a(n) _____________. Ans: cyanohydrin

Topic: Wittig Reaction

88. The reaction between a phosphorus ylide and an aldehyde or ketone is called the ___________ reaction. Ans: Wittig

Topic: Wittig Reaction

89. The driving force for the Wittig reaction is the formation of the very strong _______________ bond in _______________. Ans: P-O bond; triphenylphosphine oxide

Topic: General

90. A “green” version of the __________________ uses a tin-zeolite catalyst with hydrogen peroxide. Ans: Baeyer-Villiger oxidation

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Topic: Functional Group Tests

91. 2,4-DNP is a reagent frequently used for functional group tests; it detects the presence of _____________. Ans: aldehydes and ketones

Topic: Functional Group Tests

92. The Tollens test, used in conjunction with 2,4-DNP, can distinguish between ______________ and _______________. Ans: aldehydes and ketones

Topic: Functional Group Tests

93. What reagent would help you distinguish between acetophenone and 2-methylbenzaldehyde? Ans: Tollen’s Reagent

Topic: Functional Group Tests

94. Oximes are formed when aldehydes and ketones react with _______________. Ans: Hydroxylamine, NH2OH

Topic: Synthetic Strategy

95. Suggest a synthetic strategy for the synthesis of 3-heptanone from 1-bromobutane. Ans:

Br CNNaCN

O

i. C2H5Li, Et2O

ii. H3O+

Topic: Synthetic Strategy

96. Suggest a synthetic strategy for the synthesis of 4-methylpentanal from 3-methyl-1-bromobutane. Ans:

Br CNNaCN i. DIBAL-H

ii. H2OO

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Topic: Synthetic Strategy

97. Suggest a synthetic strategy for the synthesis of 6-methyl-3-heptanol from 4-methylpentanenitrile, (CH3)2CHCH2CH2CN. Ans:

CN

CN

OR

OH

OH

i. DIBAL-H

ii. H2O

iii. C2H5MgBr, Et2O

iv. H3O+

i. C2H5MgBr, Et2O

ii. H3O+

iii. NaBH4, H2O Topic: Reaction Sequence

98. Complete the following reaction sequence, giving structural details of all significant intermediates.

?i. Br2, hν

ii. Mg, CH3CH2CN

iii. H3O+

iv. RCO3HAns:

BrO

RCO3H

O

O

Br2, hν i. Mg, CH3CH2CN

ii. H3O+

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Topic: Reaction Sequence

99. Complete the following reaction sequence, giving structural details of all significant intermediates.

O

i. EtMgBrii. H3O+, heat

i. O3ii.Zn, CH3CO2H

?

Ans:

O HO

O

O

i. EtMgBrii. H3O+, heat

i. O3ii.Zn, CH3CO2H

Topic: NMR

100. Explain clearly how you might use 1H NMR to distinguish between 2-phenylacetaldehyde and acetophenone Ans: A quick inspection of 1H NMR of the two substances would allow easy

identification and distinction between them: the expected 1H NMR spectra of the two substances are described below. 2-Phenylacetaldehyde Acetophenone C6H5CH2CHO and C6H5COCH3 3 signals 2 signals approximate δ ppm approximate δ ppm doublet (-CH2-) 2.5 singlet (-CH3) 2.0 multiplet (C6H5) 7 multiplet (C6H5) 7.2 doublet (-CHO) 9

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MULTIPLE CHOICE QUESTIONS

Topic: Acid/Base

1. Which compound would be most acidic? A) CH3CH2CH3 B) CH3CH=CH2 C) Cyclohexane (CH3)2C=O D) (CH3)2C=O E) Benzene Ans: D

Topic: Reaction Products

2. What would be the major product of the following reaction?

C6H5CH

O

CH3CH

O

+OH-

heatA)

C6H5CH2CCH3

O

B) C6H5CCH2CH

O O

C) C6H5CHCH2CH2

OH OH

D) C6H5CH2CH2CH

O

E) C6H5CH=CHCH

O

Ans: E

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Topic: Reaction Products

3. The product, C, of the following sequence of reactions,

OH-CH3CCHO

CH3

CH3

+ CH3CH2CHO AH3O+

(-H2O)B

NaBH4

CH3OHC

would be: A)

CH3CCH=CHCH2CH2OH

CH3

CH3

B)

CH3CCH=CCH2OH

CH3

CH3 CH3

C)

CH3CCH2CH2CH2OH

CH3

CH3

D)

CH3CCH2CH2CH2CH2OH

CH3

CH3

E)

CH3CCH2CHCHO

CH3

CH3 CH3

Ans: B

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Topic: Reaction Products

4. What would be the major product of the following reaction?

CH3 CH

O

+ OH-CH3CCH3

O

100 oC?

CH CH

O

C

CH3

CH3

CH3 CH CCH3

CH3CH3 CHCH2CCH3

OH

O

CH3 CH CHCCH3

O

CH3 CHC(CH3)2

OH

OH

I II III

IV VA) I B) II C) III D) IV E) V Ans: D

Topic: Reaction Products

5. What would be the major product of the following reaction?

CH3CH2CHOH-

H2O?

O

A) CH3CH2CH2OH + CH3CH2COO- B) CH3CH2CHCH2CHO

OH

C)

CH3CH2CH2OCCH2CH3

O

D) CH3CH2CHCHCHO

HO CH3

E) CH3CH2CHCCH2CH3

HO

O

Ans: D

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Topic: Reaction Products

6. What would be the major product of the following reaction?

IV

I II

V

III

?O + O

OHOH

O

O

O

OH

OH

O

O

O

OH-

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products

7. What would be the major product of the following reaction?

IV

O

I II

V

III

O

HO

OO

O

O

HO

OH

O

O

OH-

heat?+

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products

8. What would be the major product, B, of the following reaction sequence?

IV

O

I II

V

III

O

OH

O

O OH O

OH-

heat+

i. CH3Cu ii H3O+

O

A B

A) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

9. What would be the major product, B, of the following reaction sequence?

IV

O

I II

V

III

O

OHOH

OH

OH OH

O

OH

OH-

heatNaBH4 H2O+ A B

A) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products

10. What would be the major product of the following reaction? OD-

roomtemp.

?C6H5C CHCH3

O CH3+ D2O

A) C6H5C CHCH3

O CD3

B) C6H5C CDCH3

O CH3

C) CDCH3

CH3

C6D5C

O

D) CDCD3

CD3

C6H5C

O

E)

C6H5CDCHCH3

OD

CH3

Ans: B

Topic: Reaction Products

11. What would be the product of the following reaction?

CH3CH=CO2C2H5

NaCN

C2H5OH, CH3COOH?

A) CH3CH2CHCO2C2H5

CN

B) CH3CH=CHCO2CN C) CH3CH=CHCN D) CH3CHCH2CO2C2H5

CN

E)

CH3CH=CHCOC2H5

CN

OH

Ans: D

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Topic: Reaction Products

12. Select the structure of the major product formed in the following reaction.

(CH3)2C=CHCCH3

O

1. CH3Cu

2. H2OA) (CH3)3CCH2COCH3 B) (CH3)2C=CHC(CH3)2

OH

C) (CH3)2CHCHCOCH3

CH3

D) CH3CCH3

O

2

E) (CH3)2C=CHCCH3

H

OH

Ans: A

Topic: Reaction Products

13. What would be the product of the following reaction?

C6H5CH

O

+ CH3CH2CNEtO-, EtOH

?A) C6H5CH=CHCH2CN B)

C6H5CCHCN

O

CH3

C) C6H5CH=CCN

CH3

D) C6H5CHCH2CH2CN

OH

E) C6H5CCH2CH2CN

OH

OCH2CH3

Ans: C

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Topic: Reaction Products

14. What would be the final product of the following reaction sequence?

C6H5CH

OOH-, heat

+ CH3CCH3

O

ALiAlH4

etherFinal

Product

A) C6H5CH2CH2CH2CH3 B)

C6H5CHCH2CCH3

OH O

C)

C6H5CH2CH2CCH3

O

D)

C6H5CH=CHCHCH3

OH

E)

C6H5CHCH2CHCH3

OH OH

Ans: D

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Topic: Reaction Products

15. What would be the major product of the following reaction?

C6H5CCHCH2CH3

O

CH3

+ Br2H3O+

?

A)

C6H5CCBrCH2CH3

O

CH3

B)

C6H5CCHCHCH3

O

CH3

Br

C)

C6H5CCHCHCH3

O

CH3

OH

D) C6H5CBr2CHCH2CH3

CH3

E) m-BrC6H4CCHCH2CH3

O

CH3

Ans: A

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Topic: Reaction Products

16. What would be the major product of the following reaction?

C6H5CH

O

+ CH3CCH3

O

?OH-

heatA)

C6H5CCH2CHCH3

O OH

B)

C6H5CCH2CCH3

O O

C)

C6H5CHCH2CHCH3

OH OH

D)

C6H5CCH2CCH3

O O

E)

C6H5CH=CHCCH3

O

Ans: E

Topic: Reaction Products

17. What would be the product, C, of the following reaction sequence?

(CH3)3CCH + CH3CH2CH

OO OH- H3O+

heatA B

H2

NiC

A) (CH3)3CCH2CH2CH2OH B)

(CH3)3CCHCH2CH2CH

OOH

C) (CH3)3CCH2CHCH2OH

CH3

D) (CH3)3CCH=CCH2OH

CH3

E)

(CH3)3CCH=CCH

CH3

O

Ans: C

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Topic: Reaction Products

18. What would be the product, C, of the following reaction sequence?

(CH3)3CCH + CH3CH2CH

OO OH- H3O+

heatA B C

CH2 P(C6H5)3

A) (CH3)3CCH2CH2CH2OH B)

(CH3)3CCHCH2CH=CH2

OH

C) (CH3)3CCH2C=CH2

CH3

D) (CH3)3CCH=CCH=CH2

CH3

E)

(CH3)3CCHCHCH=CH2

CH3

OH

Ans: D

Topic: Reaction Products

19. What would be the product, B, of the following reaction sequence?

C6H5CH + CH3CNEtO-, EtOH A (C9H7N)

H3O+

heatB

O

A) C6H5CH=CHCO2H B)

C6H5CCH2CO2H

O

C) C6H5CH2CH2CO2H D)

C6H5CHCH2CO2H

OH

E) C6H5CHCH2CN

OH

Ans: A

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Topic: Reaction Products

20. What would be the product, C, of the following reaction sequence?

C6H5CHOH- H3O+, heat

A B CO

CH3CH2CH

O

+25 oC (-H2O)

NaBH4

CH3OHA)

C6H5CCHCH2OH

O

CH3

B) C6H5CHCHCH2OH

HO CH3

C) C6H5CH2CHCH

CH3

O

D) C6H5CH=CCH

CH3

O

E) C6H5CH=CCH2OH

CH3hi

Ans: E

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Topic: Reaction Products

21. What would be the product, C, of the following reaction sequence?

C6H5CHOH- H3O+, heat

A B CO

CH3CH2CH

O

+25 oC (-H2O)

H2, Ni

highpressure

A) C6H5CCHCH2OH

O

CH3 B) C6H5CH2CHCH2OH

CH3

C) C6H5CH2CHCH

CH3

O

D)

C6H5CH=CCH

CH3

O

E) C6H5CH=CCH2OH

CH3 Ans: B

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Topic: Reaction Products

22. What would be the major product of the following reaction?

C6H5CH=CHCCH3

O

+ CN-CH3CH2OH

CH3COOH?

A) C6H5CH2CHCCH3

CN

O

B)

C6H5CHCH2CCH3

O

CN

C)

C6H5CH2CH2CCH3

OH

CN

D)

C6H5CH2CH2CCN

O

E)

C6H5CHCH=CCH3

CN

OH

Ans: B

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Topic: Reaction Products

23. What would be the major product(s) of the following reaction? O

Cui.ii. H3O+ ?

IV

I II

V

III

O OH O

OH O

A) I and V B) II and IV C) I and III D) III and IV E) None of these Ans: A

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Topic: Reaction Products

24. What would be the major product of the following reaction?

IV

I II

V

III

O O

OHO

O

O

O

O

OH-

O

O

O

?

A) I B) II C) III D) IV E) V Ans: E

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Topic: Reaction Products

25. What would be the major product of the following reaction?

IV

I II

V

III

O

O

Br

HO

O

Br

OO

Br

O

?i. Br2, NaOH

ii. H3O+

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reaction Products

26. What would be the major product of the following reaction sequence?

IV

I II

V

IIIO

?i. LDAii. C2H5I

O

O O

O

A) I B) II C) III D) IV E) V Ans: I

Topic: Synthetic Strategy

27. What synthetic strategy would accomplish the following transformation?

O O?

A) i) Br2, H3O+; ii) NaOC2H5, C2H5OH, heat B) i) Cl2, FeCl3; ii) NaOC2H5, C2H5OH, heat C) i) HCN; ii) H3O+

, heat D) i) Br2, hν; ii) (CH3)3COK, (CH3)3COH, heat E) i) Br2, H3O+; ii) (CH3)3COK, (CH3)3COH, heat Ans: A

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Topic: Reaction Products

28. What would be the major product of the following reaction?

CCHCH3

O

CH3

+ Br2OH-

?

CCHCH3

O

CH3Br

CCHCH3

O

CH3

Br CCBrCH3

O

CH3

CCHCH2Br

O

CH3

CCHCH2Br

O

CH2Br

I II III

IV V

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

29. Which compound would be formed when 2-methylbutanal is treated with a solution of NaOD in D2O? A) CH3CH2CDCHO

CH3

B) CH3CH2CHCDO

CH3

C) CH3CHDCHCHO

CH3

D) CH2DCH2CHCHO

CH3

E) CH3CH2CDCDO

CH3

Ans: A

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Topic: Reaction Products

30. Which compound would be formed when 2,3-dimethylhexanal is treated with a solution of NaOD in D2O? A)

O

D

B)

OD

D

C)

O

D

D)

OD

E) O

D Ans E

Topic: Reaction Products

31. What is the final product of this reaction sequence?

H2C=OCH3CH2NO2

OH-

H2, Ni?

A)

CH3C=CH2

NH2

B) CH3CH2CH2NH2 C)

CH3CHCH3

NH2

D) CH3CH2CH2NO2 E)

CH3CHCH3

NO2

Ans: C

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Topic: Reaction Products

32. Which of these is a product of the reaction of C6H5MgBr with

C6H5CH=CHCCH3

O

?

A)

C6H5CH=CCCH3

C6H5

O

B)

C6H5CH=CHCCH3

OH

C6H5

C)

C6H5CH=CHCCH2C6H5

O

D)

CH=CHCCH3

O

C6H4p-C6H5

E)

C6H5CH=CHCHCH3

OC6H5

Ans: B

Topic: Reaction Products

33. What is the product of the reaction below?

O

OC6H5

O

C6H5

O

C6H5

OC6H5

HO C6H5

I II III IV V

1. (C6H5)2CuLi

2. H2O?

A) I B) II C) III D) IV E) V Ans: B

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

34. Which reagents would you use to synthesize this compound by an aldol condensation?

C6H5CH=CHCC6H5

O

A) C6H5CH

O

C6H5CH2CH

O

andB)

C6H5CH2CH

O

and C6H5CCH3

O

C)

C6H5CH=CHCH

O

and C6H5OHD)

C6H5CH

O

andC6H5CCH3

O

E)

(C6H5)2CuLi and CH2=CHCC6H5

O

Ans: D

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

35. What starting compound(s) would you use in an aldol reaction to prepare

CH

O

O

?

CH3CHCH2CH2CCH3

OH O

CH3CCH2CH2CCH3

O O

CH3CCH2CH2CH2CH

O O

HCCH2CH2CH2CH

O O

+ H2C=O

I II III

IV VA) I B) II C) III D) IV E) V Ans: D

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

36.

Which reagents would you use to synthesize this compound by an aldol condensation?

C6H5CH=CCH

O

C6H5

A) C6H5CH

O

C6H5CH2CH

O

andB)

C6H5CH2CH

O

and C6H5CCH3

O

C)

C6H5CH=CHCH

O

and C6H5OHD)

C6H5CH

O

andC6H5CCH3

O

E) C6H5CHCH

O

C6H5CH2Cl and

ONaAns: A

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

37. The aldol condensation product formed from 3-pentanone in the presence of base has the IUPAC name: A) 5-Ethyl-4-methyl-4-hepten-3-one B) 5-Ethyl-4-methyl-5-hepten-3-one C) 4-Methyl-4-nonen-3,7-dione D) 3-Ethyl-4-methyl-3-hepten-5-one E) 3-Ethyl-4-methyl-2-hepten-5-one Ans: A

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

38. Which of these is not among the reaction products when a crossed aldol addition occurs between ethanal and butanal? A)

CH3CHCH2C=O

OH H

B) CH3CH2CH2CHCHCH2C=O

OH

CH2CH3

H

C) CH3CHCHC=O

OH H

CH2CH3

D) CH3CH2CH2CHCH2C=O

HOH

E) CH3CH2CH2CHCHC=O

HOH

CH2CH3

Ans: B

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

39.

The retro-aldol reaction of

C6H5CH=CC=O

H

CH2CH3 gives: A)

C6H5CH2CH2C=O

H

+ CH3C=O

H

B)

C6H5CH2C=O + CH3CH2C=O

H H

C)

C6H5C=O + CH3CH2CC=O

O

H

H

D)

C6H5CH2CCH2CH3

O

+ H2C=OE)

C6H5C=O + CH3CH2CH2C=O

H H

Ans: E

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

40. If butanal is added slowly to an aqueous solution of sodium hydroxide and 2,2-dimethylpropanal at 25°C, the principal product is which of these? A)

(CH3)3CCHCHC=O

OH H

CH2CH3

B)

CH3CH2CH2CHCHC=O

OH

CH2CH3

H

C)

(CH3)3CCHCC(CH3)3

OH

O

D)

CH3CH2CH2CHC(CH3)3

OH

E)

CH3CH2CH2CHCHC=O

OH

C(CH3)3

H

Ans: A

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

41. What compound results from the aldol cyclization of

CH3CCH2CH2CHCH2CCH3

O

CH3

O

?

CH3

O

CH3

CH3

O

CH3

CH3

CH3 O

CH3

CH3

CH3 O

CH3

I II III IV A) I B) II C) III D) IV E) Both III and IV Ans: E

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

42.

The aldol cyclization of CH3CCH2CH2CH2C=O

O H

produces which of these?

I II III IV

C

O

CH3 C=O

H OC=O

H OO O

CH3CH3

V

A) I B) II C) III D) IV E) V Ans: D

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

43. What product results from the intramolecular aldol reaction of 2,5-hexanedione?

I II III IV V

CH3 CCH3

O

CH3 CCH3

O

CH3

OO

CH3

O

CH3

A) I B) II C) III D) IV E) V Ans: A

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

44.

The reaction of CH3CCH2CH2CH2CCH3

O O

with base affords which of these products?

I II III IV

C=O

HCH3

V

C=O

HCH3

O

CH3

O

CH3

O O

A) I B) II C) III D) IV E) V Ans: D

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

45. The aldol reaction of cyclohexanone produces which of these self-condensation products?

I II III IV V

O O O O OO

A) I B) II C) III D) IV E) V Ans: B

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

46. Which is the only one of these compounds which cannot self-condense in the presence of dilute aqueous alkali? A) Phenylethanal B) Propanal C) 2-Methylpropanal D) 3-Methylpentanal E) 2,2-Dimethylpropanal Ans: E

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

47. Which is the only one of these compounds which cannot self-condense in the presence of dilute aqueous alkali? A) Phenylethanal B) 2-methyl-3-pentanone C) 2-Methylpentanal D) Acetophenone E) 2,2-Dimethylpentanal Ans: E

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

48. Which of these compounds cannot self-condense in the presence of dilute aqueous alkali? A) 3-(4-Nitrophenyl)propanal B) 2-methyl-3-pentanone C) 2-(4-Nitrophenyl)propanal D) 3-(4-Nitrophenyl)-2-butanone E) All of the above compounds can self-condense Ans: E

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

49. Which of these compounds can react with 4-methylhexanal to afford good yields of the crossed aldol product? A) 3-(4-Nitrophenyl)propanal B) 2-methyl-3-pentanone C) 2-(4-Nitrophenyl)propanal D) 3-(4-Nitrophenyl)-2-butanone E) None of the above compounds will give good yields of the crossed aldol product

with 4-methylhexanal Ans: E

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

50. Which of these compounds can react with 4-methylpentanal to afford good yields of the crossed aldol product? A) 3-(4-Nitrophenyl)propanal B) 2ethyl-2-methylheptanal C) 2-(4-Nitrophenyl)propanal D) 3-(4-Nitrophenyl)-2-butanone E) None of the above compounds will give good yields of the crossed aldol product

with 4-methylhexanal Ans: B

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Topic: The Aldol Reaction/Condensation (Explicitly Identified)

51.

When CH3CCH2CH2CH2CH2CH2CCH3

O O

cyclizes in basic solution, which of these compounds will be formed?

I II III IV V

CH3

CCH3O

CCH3O

CH3CH3

CH2

CCH3O CH3

OO

O

A) I B) II C) III D) IV E) V Ans: A

Topic: The Aldol Reaction/Condensation (Explicitly Identified)

52. What final product is obtained when 2,8-nonanone is treated with base, followed by reaction with sodium borohydride?

IV

I II

V

III

OH OH

OH

O

O

A) I B) II C) III D) IV E) V Ans: A

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Topic: Chemical Tests

53. Which reagent would best serve as the basis for a simple chemical test to distinguish between 2-pentanone and 3-pentanone? A) NaOI (I2 in NaOH) B) Br2/CCl4 C) CrO3/H2SO4 D) NaHCO3/H2O E) Ag(NH3)2

+ Ans: A

Topic: Chemical Tests

54. Which reagent would best serve as the basis for a simple chemical test to distinguish between CH3CHO and CH3COCH3? A) NaOI (I2 in NaOH) B) Br2/CCl4 C) C6H5NHNH2 D) NaHCO3/H2O E) Ag(NH3)2

+ Ans: E

Topic: Chemical Tests

55. Which reagent would best serve as the basis for a simple chemical test to distinguish between

C

O

CH3C

O

CH3and ?

A) NaOI (I2 in NaOH) B) Br2/CCl4 C) CrO3/H2SO4 D) NaHCO3/H2O E) Ag(NH3)2

+ Ans: B

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Topic: Chemical Tests

56. Which of the reagents listed below would serve as the basis for a simple chemical test to distinguish between 2-methyl-1-propanol and 2-butanol? A) NaOI (I2 in NaOH) B) KMnO4 in H2O C) Br2 in CCl4 D) Cold concd H2SO4 E) CrO3 in H2SO4 Ans: A

Topic: Chemical Tests

57. A compound, C5H10O, reacts with phenylhydrazine and gives a positive iodoform test. The compound could be which of these? A)

CH3CH2CH2CH2C=O

H

B)

CH3CHCH2C=O

CH3

H

C) CH2=CHCH2CHOHCH3 D)

CH3CHCCH3

CH3

O

E)

CH3CH2CCH2CH3

O

Ans: D

Topic: Chemical Tests

58. A negative iodoform test will be observed in the case of which of these? A) Acetone B) Ethanal C) Ethanol D) 2-Butanol E) All of these will give a positive test. Ans: E

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Topic: Tautomerization and Keto-Enol Equilibrium

59. Which of the following represent tautomers? A)

CH3CH=CH O CH3CH CH=OandB) andCH3 CH=CH2

O

CH3 C

O

CH2

C) andCH3 CH=CH2

O

CH3 C

O

CH3

HD) All of these E) None of these Ans: C

Topic: Tautomerization and Keto-Enol Equilibrium

60. Which of these compounds would exist in an enol form to the greatest extent? A)

CH3COC2H5

O

B)

CH3CCH2CCH3

O O

C)

CH3CCH3

O

D) CH3CH

O

E) CH3CCH2CH2CCH3

O O

Ans: B

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Topic: Tautomerization and Keto-Enol Equilibrium

61. Which of the following is a keto-enol tautomeric pair?

O OH O OH O OH

OH

O OH O OH

and and and

and and

I II III

IV VA) I B) II C) III D) IV E) V Ans: B

Topic: Tautomerization and Keto-Enol Equilibrium

62. Which of the following would undergo racemization in base?

C6H5CC6H5

OC

CH3CH2CH2

CH3CH2

CH3

CC6H5

O

C

CH3

CH3CH2

H

CC6H5

O

C

CH3

CH3

CH3

CCH2C6H5

O

I II

III IV

A) I B) II C) III D) IV E) Both III and IV Ans: C

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Topic: Tautomerization and Keto-Enol Equilibrium

63. Which of the following would undergo racemization in base?

IV

I II

V

III

OH3C H

OH3C CH3

O

H3C CH3

O

H

O

H

A) I B) II and III C) IV and V D) I and V E) I, IV and V Ans: D

Topic: Tautomerization and Keto-Enol Equilibrium

64. Which of the following would not undergo racemization in base? A) (R)-3-methyl-4-heptanone B) (R)-3-methyl-2-heptanone C) (R)-4-methyl-2-heptanone D) (R)-2,4-dimethyl-3-heptanone E) All of the above will undergo racemization in base Ans: C

Topic: Tautomerization and Keto-Enol Equilibrium

65. Which of the following would not undergo racemization in base? A) (S)-2-phenylbutanal B) (S)-3-phenylbutanal C) (S)-3-phenyl-2-butanone D) (S)-3-methyl-2-phenylbutanal E) All of the above will undergo racemization in base Ans: C

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Topic: Tautomerization and Keto-Enol Equilibrium

66. Which of the following represent keto-enol tautomers? A)

CH3CCH2CH3

O

CH3C=CHCH3

OH

andB)

CH3CCH2CH3

O

andCH2=CCH2CH3

OH

C)

CH3CCH2CH3

O

andHOCH2CCH=CH2

O

D) More than one of these E) None of these Ans: D

Topic: Tautomerization and Keto-Enol Equilibrium

67. Simple enols are less stable than the tautomeric keto forms because: A) severe angle strain exists in the enol forms. B) fewer atoms are coplanar in the keto form. C) the enol cannot be chiral. D) the C-C π bond is weaker than the C-O π bond. E) Actually, simple enols are the more stable. Ans: D

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Topic: Tautomerization and Keto-Enol Equilibrium

68. Which would be formed when 2-methylpropanal is dissolved in D2O containing NaOD?A)

CH3CHCD

CH3

O

B)

CH3CHCH

CH2D

O

C)

CH3CDCH

CH3

O

D)

CH3CDCD

CH3

O

E)

CH3CHCHOD

CH3

D

Ans: C

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Topic: Reagents, Intermediates, and Spectroscopy

69. A compound, X, C9H10O, which reacts with I2/NaOH to give a pale yellow precipitate, gives the following 1H NMR spectrum. Singlet, δ 2.0 Singlet, δ 3.0 Multiplet, δ 7.7 Which is a possible structure for X?

IV

I II

V

III

O

O

O

OO

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reagents, Intermediates, and Spectroscopy

70. What is the missing reagent?

OH-

heat?

OA)

CH3CCH2CH2CCH3

O O

B) CH3CCH2CH2CH2CH

O O

C) CH3CCH2CH2CH2CH2CH

O O

D) CH3CCH2CH2CH2COEt

O O

E)

O=CCH2CH2CH2CH2COEt

H O

Ans: B

Topic: Reagents, Intermediates, and Spectroscopy

71.

The conversion of C6H5CCH3

O

to C6H5COH

O

is accomplished by the use of which oxidizing agent? A) Ag(NH3)2

+ B) O3 C) NaOI (I2 in NaOH) D)

RCOOH

O

E) Cu++ Ans: C

Use the following to answer questions 72-73:

H

O OHA

OH-,warm(-H2O)

B (C11H12O)H2/Ni

highpressure

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Topic: Reagents, Intermediates, and Spectroscopy

72. Consider the synthesis above in answering this question. What is compound A? A) Butanone B) Butanal C) Propanal D) 1-Butanol E) 2-Methylpropanal Ans: B

Topic: Reagents, Intermediates, and Spectroscopy

73. What is the intermediate B in the synthesis shown above?

OH OH O O O

I II III IV VA) I B) II C) III D) IV E) V Ans: D

Topic: Reagents, Intermediates, and Spectroscopy

74. Which of these would not be an intermediate or final product when C6H5CH2CN and HCHO react in basic solution and the product is treated with acid? A)

C6H5CHCN

CH2OH

B)

C6H5CCN

CH2

C) C6H5CH2C=NH

C6H5CHCN

D) C6H5CH2C=O

C6H5CHCN

E) Each of these would be either an intermediate or a final product. Ans: E

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Topic: Reagents, Intermediates, and Spectroscopy

75. The Robinson annulation reaction which produces

CH3

O uses which of the following as starting materials?

CH3

CH2

CH3

O

O

O O

CH2

CH3CH=CH2

CH2=CHC=O

H+

CH2=CHCCH3

O+ HCHO +

CH3CH=CHCCH3

O+

CH3CH=CHCCH3

O+

I II III

IV VA) I B) II C) III D) IV E) V Ans: B

Topic: Reagents, Intermediates, and Spectroscopy

76. Which compound could be subjected to a haloform reaction to produce m-chlorobenzoic acid?

CH2OH

Cl

CO2H CCH2CH3

Cl

O

CCH3

Cl

O

CH2Cl

Cl

I II III IV V

A) I B) II C) III D) IV E) V Ans: D

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SHORT ANSWER QUESTIONS

Topic: General, Active Hydrogens

77. The α-hydrogens on carbonyl carbons are unusually acidic (pKa 19-20) because: _____________. Ans: the corresponding anion is resonance-stabilized by the carbonyl

Topic: Keto-Enol Tautomerism

78. The keto and enol forms of carbonyl compounds are a special type of __________ isomer called ___________. Ans: constitutional; tautomers

Topic: Keto-Enol Tautomerism

79. The interconversion of the keto and enol forms of a carbonyl compound is called _____________. Ans: tautomerization

Topic: Epimers

80. Diastereomers that differ in configuration at only one stereogenic center are sometimes called ___________, and their interconversion is called __________. Ans: epimers; epimerization

Topic: General

81. Dissolving a halogen in aqueous sodium hydroxide provides a solution of _____________. Ans: sodium hypohalite, NaOX

Topic: Haloform Reaction

82. The haloform reaction is an efficient method for converting methyl ketones to ____________. Ans: carboxylic acids

Topic: General

83. The initial product of the aldol reaction is a β-hydroxycarbonyl compound. These dehydrate readily when heated because the product _______________. Ans: is stabilized by having conjugated double bonds

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Topic: Aldol Reaction

84. An aldol reaction that starts with two different carbonyl compounds is called a _______________. Ans: crossed aldol reaction

Topic: Kinetic/Thermodynamic Enolates

85. An unsymmetrical ketone can form two possible enolates. The enolate with the more highly substituted double bond is called the ____________. Ans: thermodynamic enolate

Topic: Kinetic/Thermodynamic Enolates

86. The kinetic enolate (the less highly substituted double bond) is favored when __________ is used as a base. Ans: LDA or lithium diisopropylamide

Topic: 1,2- /1,4- Addition

87. When α,β-unsaturated aldehydes and ketones react with nucleophiles, they do so in one of two ways. What are the two ways? Ans: simple or 1,2-addition; conjugate or 1,4-addition

Topic: Kinetic/Thermodynamic Enolates

88. When α,β-unsaturated aldehydes and ketones react with nucleophiles, simple addition is favored when _________ nucleophiles are used, while conjugate addition is preferred by ___________ nucleophiles. Ans: strong; weaker

Topic: Kinetic/Thermodynamic Enolates

89. The sequence of a Michael addition followed by an intramolecular aldol condensation is known as a ___________. Ans: Robinson annulation

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Topic: 1,2- /1,4- Addition

90. When 5-methyl-3-hepten-2-one reacts with CH3Cu, the major product expected is___________ (structure and IUPAC name). Ans: The 1,4-addition product:

O4,5-dimethyl-2-heptanone

Topic: Reaction Products: Stereochemical Outcomes

91. When optically active 2-methyl-1-phenyl-1-butanone undergoes reaction with Br2/H3O+, the product is observed to exhibit no optical activity. Explain clearly. Ans: An achiral enol is formed in presence of H3O+, which can then undergo reaction

with Br2 from both faces, to produce a racemic mixture of the brominated product; hence, no observed optical activity. The reaction with (R)-2-methyl-1-phenyl-1-butanone is shown below; the same enol and products can be formed from the (S) enantiomer.

CH3

O

H CH3

OH

H

CH3

O

Br

(S)

Br2

OH

CH3

CH3

O

Br

(R)

+

+

achiral enol

H3O+

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Topic: Multistep Reaction Sequence:

92. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

O O

O

Bri. Zn,

ii. H3O+, heat

iii. DIBAL-H

iv. H2O

v. (CH3)2CuLi

vi. H2O

?

Ans: O O

Br

O

OO

O

Oi. Zn,

ii. H3O+, heati. DIBAL-Hii. H2O

i. (CH3)2CuLiii. H2O

Topic: Multistep Reaction Sequence:

93. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

CNO

?i. , EtO-, EtOH

ii.H3O+, heatAns:

CN

O

CN CO2HEtO-, EtOHH3O+

heat

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Topic: Multistep Reaction Sequence:

94. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

ONO2

?i. Cl2, FeCl3

ii. , EtO-, EtOH

iii.H3O+

Ans: O O

Cl

NO2

NO2

OH

Cl

Cl2, FeCl3 i.

ii. H3O+ EtO-, EtOH

Topic: Synthetic Strategy

95. Suggest a reasonable synthetic strategy to carry out the following transformation. O

BrOH

Ans: O O

Br

O

OCH3

BrOH

BrOCH3O

Br2, FeBr3 i.

ii. H3O+, heat EtO-, EtOH

i. LAHii. H2O

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Topic: Multistep Reaction Sequence

96. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

O

O i. EtO-, EtOH

ii. CH3CH2NH2

?

Ans:

O

O EtO-, EtOH

O O

HN CH3CH2NH2

Topic: Reaction Products

97. There are several possible cyclization products that might be formed when 5-methyl-6-oxoheptanal undergoes intramolecular aldol condensation in presence of ethoxide. Draw the structures of all these possible products. Comment on which of these is likely to be the major product, clearly explaining your rationale. Ans: There are 3 possible products (I-III) that might be formed from the 3 theoretically

possible enolates. The rationale for predicting the major product is the following: i) aldehydes are typically more reactive toward nucleophilic addition than ketones, so I and III are more likely than II; ii) since 5-membered rings are formed much more readily than 7-membered rings, I is more likely than III.

EtO-, EtOHO

O HO

O

I

HO

O

II

HOO

IIImajor product

Topic: Reaction Products

98. What is the product of the following reaction?

O

O?

OH-

Ans:

O

O

O

OH-

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Topic: Reaction Products

99. What is the product of the following reaction? O

?i. LDA, THFii. O

Ans: O i. LDA, THFii. O

O OH

Topic: Multistep Reaction Sequence

100. What is the product of the following reaction sequence? Give structural details of all significant intermediates.

O

Oi. OH-

ii. heat

?

Ans:

O

O

O

OH-

heatO

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MULTIPLE CHOICE QUESTIONS

Topic: Nomenclature 1. Which of the following is the best name for the following compound?

O

O

A) Isobutyl ethanoate B) Ethyl isopropanoate C) 3-methylbutyl ethanoate D) Ethoxy isobutyl ketone E) Ethyl 3-methylbutanoate Ans: C

Topic: Nomenclature

2.

A correct name for O

O

is: A) 2-Methylbutyl 2-methylbutanoate B) 2-Methylbutyl 3-methylbutanoate C) 3-Methylbutyl isovalerate D) Isopentyl isovalerate E) Isopentyl isobutyrate Ans: B

Topic: Nomenclature

3.

What is the IUPAC name for

ClCl

O A) ∝-Chlorovaleryl chloride B) 2-Chloropentanoyl chloride C) 1-Chloropentanoyl chloride D) 1,2-Dichloropentanal E) 1-Chloro-1-butanecarbonyl chloride Ans: B

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Topic: Nomenclature 4.

What is the IUPAC name for O O

A) 2,3−dimethylbutyl acetate B) 2,3−dimethyl-4-oxoethanal C) 2,3−dimethylbutyl methanoate D) 2,3−dimethylbutyl methylate E) 2,3−dimethylbutyl formylate Ans: C

Topic: Nomenclature

5. Which of the following structures is 3,4-dimethylpentyl chloroformate?

H O

O Cl

I

Cl O

O

II

Cl O

O

III

O

O Cl

IV

Cl O

O

VA) I B) II C) III D) IV E) V Ans: E

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665

Topic: Nomenclature 6. Which of the following structures is N-benzyl-N-propyl-2,3-dimethylbutanamide?

N

O

III

HN

O

I

N

O

II

N

O

IV V

N

O

A) I B) II C) III D) IV E) V Ans: E

Topic: Acidity

7. In which of the following sequences are the compounds listed in order of decreasing acidity? A) CH3COOH > H2O > CH3CH2OH > HC≡CH > NH3 B) CH3CH2OH > CH3COOH > H2O > HC≡CH > NH3 C) CH3COOH > CH3CH2OH > H2O > NH3 > HC≡CH D) H2O > CH3COOH > CH3CH2OH > HC≡CH > NH3 E) CH3CH2OH > H2O > CH3COOH > HC≡CH > NH3 Ans: A

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Topic: Acidity 8. Which compound would be the strongest acid?

A) CHCl2CH2CH2CO2H B) ClCH2CHClCH2CO2H C) CH3CCl2CH2CO2H D) CH3CHClCHClCO2H E) CH3CH2CCl2CO2H Ans: E

Topic: Acidity

9. Which of the following would be the strongest acid?

IIII II

Cl

CO2H

IV VCl

CO2H

Cl

CO2H CO2H

Cl Cl

CO2HCl

Cl

A) I B) II C) III D) IV E) V Ans: C

Topic: Acidity

10. Which of the following acids would have the smallest value for pKa? A) BrCH2CH2CH2COOH B) ClCH2CH2CH2COOH C) Cl2CHCH2CH2COOH D) ICHBrCH2CH2COOH E) BrCCl2CH2CH2COOH Ans: E

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Topic: Acidity 11. Which compound would be most acidic?

Acetone A) Acetic acid B) Ethanol C) Phenol D) Acetone E) Water Ans: A

Topic: Acidity

12. In which of the following are the compounds listed in order of decreasing acidity? A) CH3CO2H > CH3CH2OH > C6H5OH > H2O B) C6H5OH > CH3CO2H > H2O > CH3CH2OH C) CH3CO2H > H2O > C6H5OH > CH3CH2OH D) H2O > CH3CO2H > C6H5OH > CH3CH2OH E) None of the above Ans: E

Topic: Acidity

13. Which of the following would be the strongest acid? A) Benzoic acid B) 4-Nitrobenzoic acid C) 4-Methylbenzoic acid D) 4-Methoxybenzoic acid E) 4-Iodobenzoic acid Ans: B

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Topic: Acidity 14. Which of the following would be the strongest acid?

A) 2,3-dimethylhexanoic acid B) 3,3-diiodopentanoic acid C) 3-iodo-4-bromopentanoic acid D) 3-chloro-4-bromohexanoic acid E) 2-fluoro-4-bromopentanoic acid Ans: E

Topic: Acidity

15. A 0.2505 g sample of an organic acid is titrated to the stoichiometric endpoint with 20.10 mL of 0.0750 M NaOH. Which of these is a possible structure for the acid? A) C6H5CO2H B) p-CH3C6H4CO2H C) m-ClC6H4CO2H D) o-NO2C6H4CO2H E) p-BrC6H4CO2H Ans: D

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

16. Which reagent would serve as the basis for a simple chemical test to distinguish between benzoic acid and benzamide? A) Cold dilute NaOH B) Cold dilute NaHCO3 C) Cold concd H2SO4 D) More than one of these E) None of these Ans: D

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Topic: Chemical Tests, Relative Reactivities, and Physical Properties 17. Which reagent would best serve as a basis for a simple chemical test to distinguish

between CH3CH2COOH and CH3COOCH3? A) Concd H2SO4 B) Br2/CCl4 C) CrO3/H2SO4 D) NaHCO3/H2O E) KMnO4/H2O Ans: D

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

18. Which reagent would best serve as the basis for a simple chemical test to distinguish between C6H5CH=CHCOOH and C6H5CH=CHCH3? A) Concd. H2SO4 B) Br2/CCl4 C) CrO3/H2SO4 D) NaHCO3/H2O E) KMnO4/H2O Ans: D

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

19. Which compound would be most reactive toward nucleophilic acyl substitution? (CH3CO)2O A) CH3CO2Na B) CH3COCl C) (CH3CO)2O D) (CH3CONH2 E) CH3CO2CH3 Ans: B

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Topic: Chemical Tests, Relative Reactivities, and Physical Properties 20. The relative reactivity of acyl compounds toward nucleophilic substitution is:

A) Amide > ester > acid anhydride > acyl chloride B) Acyl chloride > ester > acid anhydride > amide C) Ester > acyl chloride > acid anhydride > amide D) Acyl chloride > acid anhydride > ester > amide E) Acid anhydride > acyl chloride > ester > amide Ans: D

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

21. Alkaline hydrolysis of an ester involves initial attack by hydroxide ion on the carbonyl carbon. The presence of substituents on the aromatic ring of ethyl benzoate may be expected to increase/decrease the rate of hydrolysis of this ester. In what order should the five substituents below be arranged to represent the decreasing order of the rates of hydrolysis when these substituents are present in the para- position of the aromatic ring in ethyl benzoate? A) -NO2 > -H > -Cl > -CH3 > -OCH3 B) -NO2 > -Cl > -H > -CH3 > -OCH3 C) -OCH3 > -CH3 > -Cl > -H > -NO2 D) -Cl > -NO2 > -H > -OCH3 > -CH3 E) -H > -Cl > -CH3 > -OCH3 > -NO2 Ans: B

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

22. Which of the following will not undergo hydrolysis, whether acid or base is present? A) CH3COCl B) CH3CONH2 C) (CH3CO)2O D) CH3CO2CH2CH3 E) CH3COCH2CH2CH3 Ans: D

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Topic: Chemical Tests, Relative Reactivities, and Physical Properties 23. Which of these compounds could not be formed by nucleophilic attack by an

appropriate reagent on acetyl chloride? A) CH3CONH2 B) CH3CO2CH2CH3 C) ClCH2COCl D) CH3CO2H E) (CH3CO)2O Ans: C

Topic: Chemical Tests, Relative Reactivities, and Physical Properties

24. In which of these species are all the carbon-oxygen bonds of equal length? A) Diethyl carbonate B) Methyl butanoate C) Lithium acetate D) Propionic anhydride E) Pentanoic acid Ans: C

Topic: Reaction Products

25. What is the expected product, A, of the following reaction sequence? i. NaCNii. 70% H2SO4, reflux

A + NH4+Cl

A) HCO2CH2C6H5 B) C6H5CH2COOH C) C6H5CH2OSO3H D) C6H5CHClCOOH E) O=C(CH2C6H5)2 Ans: B

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Topic: Reaction Products 26. Predict the major organic product of the reaction sequence below:

I II III

IV V

OHOH

OH

CO2H

CHO

CHO

+ KMnO4 heat

H2O, OH−?

H3O+

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reaction Products 27. What would be the product of the following reaction ?

OH

O

OH

O

O

O

O

O

O

O

O

O O

O

I II III

II III

HA+ ?18

18 18

18

18 18

\ A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

28. What would be the final product, F, of the following sequence of reactions?

CO2H

Br Br CO2H CO2H CO2HO

OI II III IV V

i. LAH, Et2Oii. H2O

i. Mg, Et2O

ii. CO2

iii. H3O+

FPBr3

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products 29. The product, Z, of the following sequence of reactions is which compound?

i. KMnO4, OH−, heat

ii. H3O+

iii. SOCl2iv. CH3CH2OH, base

I II III

IV V

O

Zp-Chlorotoluene

Cl Cl

Cl Cl

OO

OO

OCl

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reaction Products 30. Predict the major organic product, P, of the following sequence of reactions:

CO2H

Cl

ClO

O CO2H

O O

O

O

O

ClO

O

I II III

IV V

H2 cat.

Pi. SOCl2ii. CH3OH

i. OH− (2eq.), H2O heat

ii. H3O+

A) I B) II C) III D) IV E) V Ans: D

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Topic: Reaction Products 31. Predict the major organic product of the reaction sequence,

OO O

HO

OOH

OHO

ONH2

OH2N

ONH2

O

OHN O

I II III

IV V

HNO O

Mi. NH3, H2O ii. dilute HCl, cold

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

32. (R)-3-hexanol is subjected to the following sequence of reactions: i) acetyl chloride, pyridine; ii) NaOH(aq), heat. What is(are) the likely final product(s)? A) (R)-3-hexanol B) (S)-2-hexanol C) Equal amounts of A) and B) D) 2-Hexene (cis and trans) E) 1-Hexen-2-ol Ans: A

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Topic: Reaction Products 33. What would be the final product?

C6H5CH2CONH2i. CH3MgI, Et2O

ii. H3O+P4H10heat

?

A) C6H5CH2CO2CH3 B) C6H5CH2CH2NHCH3 C) C6H5CH2COCH3 D) C6H5CH2CH(CH3)CN E) C6H5CH2CH=NCH3 Ans: C

Topic: Reaction Products

34. Predict the final product likely to be obtained when (S)-2-methyl-3-pentanol is subjected to the following sequence of reactions: i) benzoyl chloride; ii) NaOH (aq), heat A) (S)-2-methyl-3-pentanol B) (R)-2-methyl-3-pentanol C) (R,S)-2-methyl-3-pentanol D) 2-methyl-2-pentene E) (R,S)-2-methyl-3-pentanol and 2-methyl-2-pentene in more or less equal amounts Ans: A

Topic: Reaction Products

35. Predict the final product likely to be obtained when (S)-2-methyl-3-pentanol is subjected to the following sequence of reactions: i) Tosyl chloride; ii) NaOH (aq), heat A) (S)-2-methyl-3-pentanol B) (R)-2-methyl-3-pentanol C) (R,S)-2-methyl-3-pentanol D) 2-methyl-2-pentene E) (R,S)-2-methyl-3-pentanol and 2-methyl-2-pentene in more or less equal amounts Ans: B

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Topic: Reaction Products 36. The product of the following reaction is:

I II III

IV V

OCO2H

O

OO

ClH

O

O

O

CO2H

OCl

O

OO

O OHO O

O

O

O

OH+ heat

(1 mol) (1 mol)

?

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

37. What final product, Q, would be obtained via the following reaction sequence?

H

H

H3C

OHClC6H5

O

OC6H5

OQ +pyridine

OH−/ H2O

heat

A) cis-3-Methylcyclopentanol B) trans-3-Methylcyclopentanol C) Equal amounts of A) and B) D) 3-Methylcyclopentanone E) None of these Ans: B

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Topic: Reaction Products 38. What would be the final organic product of the following reaction?

C6H5 ClNaCN i. excess LAH, Et2O

ii. H2O?

A) C6H5CH2CH2CO2H B) C6H5CH2CH2NH2 C6H5CH2CH(CH3)CN C) C6H5CH2CH(CH3)CN D) C6H5CH2CH=NH E) C6H5CH2NH2 Ans: B

Topic: Reaction Products

39. What would be the final organic product of the following reaction?

i. LAH, Et2Oii. H2OBr ?

i. Mg, Et2O

ii. CO2

iii. H3O+

A) (CH3)3CCO2H B) (CH3)3CCOCH3 C) (CH3)3CCH2OH D) (CH3)3COCH3 E) (CH3)3CCO2CH3 Ans: C

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Topic: Reaction Products 40. Identify the product(s) of the following reaction.

OCO2H

O

O

OH O

CO2H

I II III

IV V

O

O

CO2H

heat?

+ CO2

+ CO 2

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

41. What would be the final product? CO2H i. PCl5

ii. NH3iii. P4H10, heat

?

A) CH3CH2CH2NH2 B) CH3CH2CONH2 C) CH3CH2CONHCOCH2CH3 D) CH3CH2CN E) CH3CH2COO-NH4

+ Ans: D

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Topic: Reaction Products 42.

What is the final product of this sequence of reactions?

I II III

IV V

Br

O

ONH2 CN

NH2NHCl

O

NH2

O

i. SOCl2ii. excess NH3

?i. Mg, Et2O

ii. CO2

iii. H3O+

A) I B) II C) III D) IV E) V Ans: C

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Topic: Reaction Products 43. What is the product of the reaction of 1-propanol with phenyl isocyanate, C6H5N=C=O?

A) C6H5

HN O

O

B) C6H5

NCO2H

C)

C6H5N

O

CHO

D)

C6H5

HN O

O E)

C6H5

HN

O Ans: A

Topic: Reaction Products

44. What would be the final product of this reaction sequence?

I II III

V

CN NH2

O

HN

HN

O

NH2

CO2H

IV

CO2 NH4

i. PCl3ii. NH3iii. P4O10

?

A) I B) II C) III D) IV E) V Ans: A

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Topic: Reaction Products 45. What is the ultimate product of this sequence of reactions?

Cl NH

O

IV

O Cl

O

HN

HN

OO N

H

O

Cl Cl

O

I II III

O O

O

V

CH3NH2CH3CH2OH (1 eq.)

?

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

46. What is the product of this reaction?

O

O

CO2HO HOO

O

IIII II

O O

O

O

O

O

O

IV V

OOHO

?CH3OH

A) I B) II C) III D) IV E) V Ans: B

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Topic: Reaction Products 47. What is the product of the reaction of propanamide with methylmagnesium bromide (1

eq.)? A)

NH

O

B)

N

O

C) O

D)

NHMgBr

O+ CH4

E) O

H2NOMgBr

Ans: D

Topic: Reaction Products

48. What is the final product obtained when toluene is subjected to the following reaction sequence? i) Cl2 (large excess), heat, hν; ii) OH−/H2O, heat; iii) H3O+

I II III

IV V

OHOH

OH

CCl3HO

CO2H

OHCl

Cl Cl

CCl3

HO

A) I B) II C) III D) IV E) V Ans: B

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Topic: Structure Identification (Spectroscopy) 49. A compound has the molecular formula, C6H12O2. Its IR spectrum shows a strong

absorption band near 1740 cm-1; its 1H NMR spectrum consists of two singlets, at δ 1.4 and δ 2.0. The most likely structure for this compound is:

O O O

O O H

I II III

IV V

O O O

O O

A) I B) II C) III D) IV E) V Ans: D

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Topic: Structure Identification (Spectroscopy) 50. A compound has the molecular formula C8H14O4. Its IR spectrum shows a strong

absorption band near 1740 cm-1. Its 1H NMR spectrum consists of: triplet, δ 1.3 singlet, δ 2.6 quartet, δ 4.2 The most likely structure for the compound is:

IV V

O

OO

O O

O

O

OO

OO

OI II III

HO2C CO2H O OO

O

A) I B) II C) III D) IV E) V Ans: A

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Topic: Structure Identification (Spectroscopy) 51. A compound with the molecular formula C5H10O2 gave the following 1H NMR

spectrum: triplet, δ 0.90 multiplet, δ 1.60 singlet, δ 1.95 triplet, δ 3.95 The IR spectrum showed a strong absorption band near 1740 cm-1. The most likely structure for the compound is: A) O

O B) O

O C) O

O D) OH

O E)

HO

O

Ans: A

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Topic: Structure Identification (Spectroscopy) 52. A compound with the molecular formula C18H18O4 has a 1H NMR spectrum that

consists of: singlet, δ 2.7 singlet, δ 3.1 multiplet, δ 7.3 The IR spectrum shows a strong absorption band near 1750 cm-1. The most likely structure for the compound is: A) O O C6H5

O

OC6H5

B) O O C6H5

O

C6H5

O

C) O C6H5OC6H5

O

O

D) O C6H5

OOC6H5

O

E) O C6H5OC6H5

O

O

Ans: C

Topic: Structure Identification (Spectroscopy) 53. The IR spectrum of a compound exhibits a broad absorption band at 2500-3000 cm-1

and a sharp band at 1710 cm-1. Which of these compounds could it be? A) 1-Butanol B) Propyl acetate C) Butanoic acid D) Acetyl chloride E) Acetic anhydride Ans: C

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Topic: Synthesis 54. Which of the following reactions would constitute a reasonable synthesis of propyl

acetate? A) OH

OH

O

HA+

B) OHCl

O+

pyridine

C) OHO

O+

O

D) All of these E) None of these Ans: D

Topic: Synthesis

55. Which of the following would serve as a synthesis of 2,2-dimethylpropanoic acid? A) Br

i. Mg, Et2O

ii. CO2

iii. H3O+

B) i. KMnO4, OH−, heat

ii. H3O+

OH

C) Bri. CN−

ii. OH−, H2O, heat

iii. H3O+

D) All of these E) Answers A) and B) only Ans: E

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Topic: Synthesis 56. Which of the reactions listed below would serve as a synthesis of acetophenone,

C6H5COCH3 ? A)

C6H5 Cl

O+ (CH3)2CuLi

B) H3C Cl

O AlCl3+ C6H6

C) C6H5 OCH3

O+ CH3MgI

D) Two of these E) All of these Ans: D

Topic: Synthesis

57. Which of the following would serve as syntheses of (CH3)3CCO2H? A) i. Cl2/OH− (excess)

ii. H3O+

O

B) Bri. CN−

ii. H3O+ (heat)

C) Bri. Mg, Et2O

ii. CO2

iii. H3O+

D) Answers A) and B) only E) Answers A) and C) only Ans: E

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Topic: Synthesis 58. Which of the reactions listed below would serve as a synthesis of benzyl acetate,

CH3CO2CH2C6H5 ? Benzyl alcohol + acetic anhydride A) Benzyl alcohol + acetic anhydride B) Benzyl alcohol + acetic acid + H3O+ C) Benzyl alcohol + acetyl chloride D) Answers A) and C) only E) Answers A), B), and C) Ans: E

Topic: Synthesis

59. Which reactant is unlikely to produce the indicated product upon strong heating? A) 2,2-dimethylpropanedioic acid 2-methylpropanoic acid B) 2-ethylpropanedioic acid Butanoic acid C) 2-methyl-3-oxo-pentanoic acid 3-Pentanone D) 2-methyl-4-oxo-pentanoic acid 2-Methyl-3-butanone E) 4-methyl-3-oxo-heptanoic acid 3-Methyl-2-hexanone Ans: D

Topic: Synthesis

60. N,N-Dimethylbenzamide can be made from which of the following? A)

O

OC6H5 NH

+

B) O

ClC6H5 NH+

C) O

OC6H5 C6H5

ONH+

D) O

NH2C6H5 CH3MgCl+

E) A), B), and C) only Ans: E

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Topic: Synthesis 61. Choose the reagent(s) that would bring about the following reaction:

CH3CH2CH2COOH ⎯⎯⎯→ CH3CH2CH2CH2OH A) H2/Ni B) Li/liq NH3 C) LiAlH[OC(CH3)3]3 D) NaBH4, CH3OH E) LiAlH4, ether Ans: E

Topic: Synthesis

62. Choose the reagent(s) that would bring about the following reaction: CH3CH2CH2CO2CH3 ⎯⎯⎯→ CH3CH2CH2CHO A) H2/Ni B) Li/liq NH3 C) LiAlH[OC(CH3)3]3 D) NaBH4, CH3OH E) LiAlH4, ether Ans: C

Topic: Synthesis

63. Choose the reagent(s) that would bring about the following reaction: CH3C≡CCO2CH3 ⎯⎯⎯→ (E)-CH3CH=CHCO2CH3 A) H2/Ni B) Li/liq NH3 C) LiAlH[OC(CH3)3]3 D) NaBH4, CH3OH E) LiAlH4, ether Ans: B

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Topic: Synthesis 64. Choose the reagent(s) that would bring about the following reaction:

CH3C≡CCH2CO2CH2CH3 ⎯⎯⎯→ CH3CH≡CHCH2CH2OH A) H2/Ni B) Li/liq NH3 C) LiAlH[OC(CH3)3]3 D) NaBH4, CH3OH E) LiAlH4, ether Ans: E

Topic: Synthesis

65. Which of the following compounds is capable of forming a δ-lactone? A) 5-hydroxypentanoic acid B) Pentanedioic acid C) 4-hydroxypentanoic acid D) 3-hydroxypentanoic acid E) 2-hydroxypentanoic acid Ans: A

Topic: Synthesis

66. Which of the following reactions could be used to synthesize ethyl acetate? A) CH3CH2OH + (CH3CO)2O + pyridine ⎯⎯⎯→ B) CH3CH2OH + (CH3CO)2O ⎯⎯⎯→ C) CH3CH2OH + CH3CO2H + H3O+ ⎯⎯⎯→ D) Answers A) and C) only E) Answers A), B), and C) Ans: E

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Topic: Synthesis 67. Which of the following would yield (S)-2-butanol?

A) i. CH3CO2−Na+

ii. OH−, H2O, heat(R)-2-Bromobutane

B) OH−, H2O, heat(R)-2-Bromobutane

C) OH−, H2O, heat(S)-sec-Butyl acetate

D) All of these E) None of these Ans: D

Topic: Synthesis

68. Which of the following would serve as a reasonable synthesis of ethyl benzoate? A)

O

OHC6H5 OH+ HA reflux

excessB)

O

ClC6H5 OH+ base

C) O

OC6H5 C6H5

OOH+

D) All of the above E) None of the above Ans: D

Topic: Synthesis

69. On theoretical grounds, one would predict that the (1:1) reaction of acetic propionic anhydride with methyl alcohol would form chiefly: A) Methyl acetate + propionic acid B) Acetone + propionic acid C) Methyl propionate + acetic acid D) Methyl acetate + acetic acid E) Methyl ethyl ketone + acetic acid Ans: A

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Topic: Synthesis 70. Which of the following combinations of reagents would not produce an ester?

A) O

OAgH3CBr+

B) O

ONaH3COH+

C) HAO

OHH3COH+

D) O

OH3C CH3

O

OH+

E) +O

ClH3COH

Ans: B

Topic: Synthesis 71. Which carboxylic acid would decarboxylate when heated to 100-150°C?

HO2CCO2H

I

CO2HO

II

HO2C CO2H

IIIA) I B) II C) III D) More than one of these E) None of these Ans: D

Topic: Methods and Miscellaneous

72. An acid chloride is prepared from the related carboxylic acid by reaction with which of these? A) HCl B) Cl2 C) SOCl2 D) HOCl E) AlCl3 Ans: C

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Topic: Methods and Miscellaneous 73. Which of the following is not a method for preparing butanoic acid?

A) CH3CH2CH2Br + NaCN; then H3O+, reflux B) CH3CH2CH2MgBr + CO2; then H3O+ C) CH3CH2CH2OH + CO D) CH3CH2CH2CO2Et + OH−/H2O; then H3O+ E) CH3CH2CH2CH2OH + KMnO4/OH−/H2O/heat; then H3O+ Ans: C

Topic: Methods and Miscellaneous

74. Intramolecular dehydration to form a cyclic monoester is most likely to occur when which of the following is heated with acid? A) CH3CH2CH2CHOHCO2H B) CH3CH2CHOHCH2CO2H C) CH3CH2CH2CH2CO2H D) CH3CHOHCH2CH2CO2H E) HO2CCH2CH2CO2H Ans: D

Topic: Methods and Miscellaneous

75. Which of these combinations will not produce benzoic acid? A) C6H5CH2OH + KMnO4/OH−/H2O, heat; then H3O+ B) C6H5CH3 + KMnO4/OH−/H2O, heat; then H3O+ C) C6H6 + CO2, high pressure D) C6H5COCH3 + Cl2/OH−/H2O; then H3O+ E) C6H5COCl + OH−/H2O; then H3O+ Ans: C

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Topic: Methods and Miscellaneous 76. Reasoning by analogy, one would predict that the reaction of carbon disulfide with sec-

butylmagnesium bromide should yield which of the following (after acidification)?

SH

S

I

SH

II

SH

S

III

S

IV

S

SH

VA) I B) II C) III D) IV E) V Ans: A

Topic: Methods and Miscellaneous

77. γ - And δ-hydroxy acids can be esterified intramolecularly to form compounds known as which of these? A) Anhydrides B) Cycloalkenes C) Lactones D) Lactams E) Cyclic ketones Ans: C

Page 698: 45669583 Organic Practice

Chapter 18

698

Topic: Methods and Miscellaneous 78. Which of the following statements concerning nitriles is incorrect?

A) Nitriles can be hydrolyzed to carboxylic acids. B) Nitriles can be formed from (many) alkyl halides by nucleophilic substitution by

cyanide ion. C) Nitriles can be reduced with excess lithium aluminum hydride to primary amines,

RNH2. D) Nitriles react with Grignard reagents to form tertiary alcohols. E) Nitriles can be made by the dehydration of amides. Ans: D

SHORT ANSWER QUESTIONS

Topic: Nomenclature 79. While the IUPAC name for HCO2H is methanoic acid, it is commonly known as

__________. Ans: formic acid

Topic: Nomenclature

80. Ethanoic acid (CH3CO2H) is usually called _______________, from the Latin for “vinegar”. Ans: acetic acid

Topic: Reaction Mechanisms

81. Acyl compounds tend to react by acyl substitution mechanisms because they all have a good or reasonably good ________________ attached to the carbonyl carbon. Ans: leaving group

Topic: Miscellaneous

82. Cyclic esters are called _____________, while cyclic amides are called _________. Ans: lactones; lactams

Page 699: 45669583 Organic Practice

Chapter 18

699

Topic: Methods and Miscellaneous 83. An acid-catalyzed esterification (a reaction between a carboxylic acid and an alcohol) is

called a ________________. Ans: Fischer esterification

Topic: Methods and Miscellaneous

84. Base-promoted hydrolysis of esters is sometimes called ______________. Ans: saponification

Topic: Methods and Miscellaneous

85. The linkages that join amino acids together to form proteins are primarily ___________ bonds. Ans: amide

Topic: Methods and Miscellaneous

86. Litmus paper turns ___________ when an aqueous solution of a carboxylic acid is dropped on it. Ans: red

Topic: Miscellaneous

87. The only carboxylic acid derivative with two carbonyl groups is the ___________. Ans: anhydride

Topic: Miscellaneous

88. The presence of electron-withdrawing substituents close to the carboxylic acid functional group will ___________ the acidity of the molecule by _________. Ans: increase; induction

Topic: Reactions

89. When a cyclic ketone undergoes the Bayer-Villiger oxidation, the product can be described as a ______________. Ans: lactone (cyclic ester)

Page 700: 45669583 Organic Practice

Chapter 18

700

Topic: Reactions 90. When a gamma-hydroxy acid is treated with dilute acid, cyclization occurs, producing a

______________. Ans: lactone (cyclic ester)

Topic: Miscellaneous

91. The functional group in a lactam is _________________. Ans: amide

Topic: Nomenclature

92. Draw the structure for 3-methylbutanoic anhydride. Ans:

O

O O

Topic: Nomenclature

93. Draw the structure for 3-ethyl-4,4-dimethylhexanenitrile. Ans:

CN

Topic: Nomenclature 94. Draw the structure for 3-oxo-5-bromohexanoic acid.

Ans: O

OH

OBr

Topic: Nomenclature 95. Draw the structure for 4-methylpentyl 3-ethylpentanoate.

Ans:

O

O

Page 701: 45669583 Organic Practice

Chapter 18

701

Topic: Reaction Sequence 96. Complete the following reaction sequence, giving details of all significant intermediates.

O i.) 2 equiv CH3Liii.) CH3I ?

O

Ans: O

O OLi OCH32 equiv CH3Li CH3I

Topic: Reaction Sequence

97. Complete the following reaction sequence, giving details of all significant intermediates.i.) SOCl2ii.) CH3CH2CH2NHCH3

?OH

O

Ans: OH

O

Cl

O CH3CH2CH2NHCH3N

OSOCl2

Topic: Synthetic Strategy

98. Suggest a suitable synthetic strategy for the transformation of 3-methyl-1-pentanol into propyl 3-methylpentanoate Ans:

OH

O

O

O OH

OH i. KMnO4, OH-, H2O

ii. H3O+

Cl

O

SOCl2

Page 702: 45669583 Organic Practice

Chapter 18

702

Topic: Reaction Sequence 99. Complete the following reaction sequence, giving details of all significant intermediates.

i. KMnO4, OH-, H2O

ii. H3O+

iii. NaBH4, H2O

iv. H3O+

?

Ans: i. KMnO4, OH-, H2O

ii. H3O+

OHO

O

NaBH4, H2O

OHO

OHH3O+O

O

Page 703: 45669583 Organic Practice

Chapter 18

703

Topic: Reaction Sequence, Spectroscopic Analysis 100. When propylbenzene is subjected to the sequence of reactions outlined below, the major

product is found to exhibit the following 1H NMR spectrum: d 1.2 ppm, triplet 2.2 ppm, quartet 7.5 ppm, multiplet Account for the formation of this product, giving details of all significant intermediates.

?

i. NBSii. NaOHiii. CrO3iv. RCO3H

Ans: Reaction with NBS would lead to benzylic bromination, followed by nucleophilic substitution to afford the corresponding alcohol. Oxidation with CrO3 would yield an alkyl aryl ketone, which would undergo Bayer-Villiger oxidation with a peroxy acid to afford the ester shown below (along with the likely 1H NMR signal assignment).

OH

CrO3

O

NaOH

RCO3H

Br

NBS

O

O

7.5 ppm

2.2 ppm

1.2 ppm

Page 704: 45669583 Organic Practice

Chapter 18

704

Topic: Reaction Sequence 101. Complete the following reaction sequence, giving details of all significant intermediates.

OH?i. COCl2 (1 equivalent)

ii. CH3CH2CH2CH2NHCH3

Ans: OH COCl2 (1 equivalent) O

O

Cl

O

N

O

HN

Page 705: 45669583 Organic Practice

Chapter 19

MULTIPLE CHOICE QUESTIONS

Topic: Relative Acidities 1. Which of the compounds listed below is more acidic than 1-butanol?

A) Ethyl acetoacetate B) 2-butanone C) Ethyl pentanoate D) All of these answers E) Answers A) and B) only Ans: A

Topic: Relative Acidities

2. Which of the compounds listed below is more acidic than 2-pentanol? A) Ethyl 3-oxopentanoate B) 2-pentanone C) Pentanal D) All of these answers E) Answers A) and B) only Ans: A

Topic: Relative Acidities 3. Which of the following hydrogens is the most acidic?

O

O

O

OI

II

III

IV

V

A) I B) II C) III D) IV E) V Ans: C

Page 706: 45669583 Organic Practice

Chapter 19

Topic: Relative Acidities 4. Which is the most acidic hydrogen in the compound shown?

O

O

O

vvv

v v

V

IV I

IIIII

A) I B) II C) III D) IV E) V Ans: C

Topic: Relative Acidities

5. Which of the following compounds is the strongest acid?

IV

I II

V

III

CO2Et

CNO CN

OH

NO2

CNNO2 O

O

A) I B) II C) III D) IV E) V Ans: E

Page 707: 45669583 Organic Practice

Chapter 19

Topic: Relative Acidities 6. Which of the indicated hydrogens can be replaced by alkylation?

S S

HHH

H

H

H

HH3CHH3C

(I) (II)

(III)

(IV)

(V)

A) I B) II C) III D) IV E) V Ans: C

Topic: Relative Acidities

7. Which of the indicated hydrogens is most likely to be removed upon treatment with n-butyllithium?

S S

HHH

H

H

H

HH3CHH3C

(I) (II)

(III)

(IV)

(V)

A) I B) II C) III D) IV E) V Ans: C

Page 708: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 8. What would be the major product of the following reaction?

IV

I II

V

III

OHO

OO

OH O

OO

OO O

O O

O

O

O

O

O

i. NaOC2H5

ii. H3O+ ?

A) I B) II C) III D) IV E) V Ans: C

Page 709: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 9. What would be the product of the following sequence?

IV

I II

V

III

O O

OO

O

O

O

OO

O

O

O

i. NaOC2H5, C2H5OH

ii. H3O+ ?+

O

O

O

OH O

O

A) I B) II C) III D) IV E) V Ans: A

Page 710: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 10. What is the expected product from the following reaction sequence?

IV

I II

V

III

O O

O

O O

O O

OO

O

O

O O

OO

O

O

OO O

Oi. NaOC2H5, C2H5OH

ii. H3O+ ?+

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

11. What is the product, Z, of the following reaction sequence?

IV

I II

V

III

O HN H3O+

(-H2O)PhCOCl

N Ph

O

Ph

OO

Ph

OON

Ph

O

H3O+

Ph

O

+ Z

A) I B) II C) III D) IV E) V Ans: B

Page 711: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 12. What would be the product, P, of the following reaction sequence?

IV

I II

V

III

O

O O

PhO

O

OPh

Ph O

OPh

O

Ph

O

i. NaOEtii.PhCH2Br

i. NaOHii.H3O+

heat (-CO2) P

A) I B) II C) III D) IV E) V Ans: C

Page 712: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 13. Predict the product of the following reaction sequence.

IV

I II

V

III

OH

O

O

O

OH

O

OHO

O

O

O

O

O

O O

i. NaOC2H5

ii. CH3CH2CH2Br

iii. NaOH

iv. H3O+, heat

?

A) I B) II C) III D) IV E) V Ans: D

Page 713: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 14. What is the product, W, of the following reaction sequence?

IV

I II

V

III

O O

OO

Na+..

BrBr

CO2HHO2C HO2CCO2H

O

O

CO2H

CO2EtEtO2C

Wi. NaOHii.H3O+

heat (-CO2)(2 eq) (1 eq)

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

15. Predict the product of the following reaction sequence.

IV

I II

V

III

OH

OOH

O

OH

OO

O

O

O O

O O

i. NaOEt, EtOHii. NaOH, heatiii. H3O+ iv. heat

?O

O+

O OO

O

OHO

HO

O

A) I B) II C) III D) IV E) V Ans: B

Page 714: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 16. The product, L, of the following reaction sequence,

EtO2C CO2Et NaOEt

HN NH2

MeO

O

OEt

O

O

NH

NH

O

CO2Et

EtCO2Et

EtO2C

MeEtO2C

I II

NH

O

NH

NH

NH

O O O

IV V

NH

O

H2N NH

NH2

O O O

Me Et

EtO−H2N NH2

O

NH

NH

O

O

MeEt

O

III

i. EtBrii. (CH3)3COKiii. MeI ?+

n

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

17. The product(s) of the reaction of 2 mol of ethyl butanoate with sodium ethoxide is(are): A)

OH

O+ NaOH

B)

O

O O

C)

O

O

O

D)

OO

OE)

O

O

O

Ans: C

Page 715: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 18. The reaction of diethyl heptanedioate with sodium ethoxide would give as the product:

I

III IV

II

V

EtO

O

EtO

O

O

OEt

OO O O

O

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

19. The product of the following reaction is:

I

IV V

II III

O

OH

OO

CN

CN

OOMe

O CNO

O

O CN

O NH

OMe

O

CN

O

+weak base ?

A) I B) II C) III D) IV E) V Ans: D

Page 716: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 20. Which product can be obtained via the following generalized reaction?

I

IV V

II III

EtOCN

ONaOEtEtOH

EtOCN

O

REtO

RO

EtO

O

IN

RRO

CNO

RCN

O

R-I + ?

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

21. Malonic ester (diethyl malonate) is treated successively with sodium ethoxide (1 eq.), ethyl bromide, potassium tert-butoxide, isobutyl chloride, hot aqueous NaOH, HCl, and heat. What is the final product? A) 4-Ethyl-2-methylpentanoic acid B) 6-Methylheptanoic acid C) 2-Ethyl-3-methylpentanoic acid D) 2-Ethyl-4-methylpentanoic acid E) Ethylisobutylmalonic acid Ans: D

Topic: Reaction Products 22. Malonic ester (diethyl malonate) is treated successively with sodium ethoxide (1 eq.), 1-

bromopentane, potassium tert-butoxide, iodomethane, hot aqueous NaOH, HCl, and heat. What is the final product? A) 2-Methylheptanoic acid B) 3-Methylhexanoic acid C) 3-Methylpentanoic acid D) 2-Methylpentanoic acid E) Ethyl 2-methylheptanoate Ans: A

Page 717: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 23. What is the product of the Dieckmann condensation of this diester,

I II III

EtO OEtO

O

O OEtO

O OEtO

O OEtO

A) I B) II C) III D) I and II E) I, II, and III Ans: D

Topic: Reaction Products

24. What product(s) is (are) likely to be obtained upon Dieckmann condensation of the following substance?

I II III

OO

O O

O

O O

O

O O

O

O O

O

O O

IV A) I and II B) II and III C) III and IV D) I and III E) II and IV Ans: D

Page 718: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 25. The Thorpe reaction of dinitriles is analogous to the Dieckmann condensation of

diesters. What is the product predicted to result from the use of N≡CCH2CH2CH2CH2C≡N and sodium ethoxide?

IV

NH

CNCNNC

V

CNNC

II

HN CN

III

NH

NH

I

NH

CN

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

26. What product(s) result from the Claisen condensation carried out with an equimolar mixture of ethyl acetate and ethyl propanoate?

II

O

OO

III

O

OO

IV

O

OO

I

O

OO

A) I B) II C) III D) IV E) All of these Ans: E

Page 719: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 27. What product(s) result from the Claisen condensation carried out with an equimolar

mixture of ethyl 2-methylpropanoate and ethyl propanoate?

I II III IV

O

O

O O

O

O O

O

O O

O

O

A) I and II B) I and IV C) I, II and IV D) II and III E) All of these Ans: E

Topic: Reaction Products

28. What product is finally formed when the initial compound formed from cyclohexanone and pyrrolidine is mixed with allyl chloride and that product is heated and then hydrolyzed?

II

O

V

O

IV

O

III

N

I

HO Cl

A) I B) II C) III D) IV E) V Ans: B

Page 720: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 29. What is the major product of the following reaction?

III

O

OEt

O

IV V

OEtO

OO

OEtO

O O

O OOEt

O

OEt

O

O

III

OEtO

OEt

O

O Qi. ii. H3O+

NaNH2Et2O

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

30. What is the structure for R?

IV

I II

V

III

S S

H Ph

PhCHO

Ph

CHO

CHOPh Ph

OH

R

PhO

i. C4H9Li, Et2Oii. C6H5CH2Br

HgCl2MeOH, H2O

A) I B) II C) III D) IV E) V Ans: C

Page 721: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products

31. What is the final product from the following reaction sequence?

IV

I II

V

Ph OPh

O

S S

H Ph

S SPh

S S

H Ph

III

PhS SH

i. C4H9Li, Et2Oii. C2H5Briii. HgCl2, CH3OH, H2O

?

A) I B) II C) III D) IV E) V Ans: D

Topic: Synthesis

32. Which of the following might be used to synthesize the following substance?

Ph OH

OH

A)

PhCO2EtH2OCH3CH2CO2Et

NaOEt, EtOHH3O+ LiAlH4

Et2O B)

PhCHO + CH3CHBrCH2CO2EtH2OMg

Et2OH3O+ LiAlH4

Et2OC)

CH3CHBrCH2CO2Et PhCHO H2OMgEt2O

D) Answers A) and B) E) Answers A), B), and C) Ans: A

Page 722: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 33. Which of the following might be used to synthesize the following substance?

Ph

OH

OH

A)

OPh

O

O

O

i. , NaOEt, EtOH

ii. H3O+

iii. LAH, Et2O

iv. H2OB)

OPh

O

O

O

i. , NaOEt, EtOH

ii. H3O+

iii. LAH, Et2O

iv. H2O

B.

C)

OPhO

O

Bri. , Mg, Et2O

ii. H3O+

iii. LAH, Et2O

iv. H2O

C.

D) Answers A) and C) E) Answers B), and C) Ans: B

Page 723: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 34. Which of the following could be used to synthesize the following substance in good

yield?

O

CO2H

A) Cyclohexanone, ClCH2COOH, AlCl3, heat B) Cyclohexanone, (CH3CH2)2NH, HA, (-H2O); then BrCH2COOC2H5; then OH-,

H2O, heat; then H3O+ C) Cyclohexylacetic acid, KMnO4, OH-, heat; then H3O+ D) Answers A) and B) E) Answers A), B), and C) Ans: B

Topic: Synthesis

35. Which of the following could be used to synthesize the following substance in good yield?

O OH

O

A) Cyclopentanone, ClCH2CH2COOH, AlCl3, heat B) Cyclopentanone, (CH3CH2)2NH, HA, (-H2O); then BrCH2CH2COOC2H5; then

OH-, H2O, heat; then H3O+ C) 3-(2-hydroxycyclopentyl)propanal, KMnO4, OH-, heat; then H3O+ D) Answers A) and B) E) Answers B) and C) Ans: E

Topic: Synthesis

36. Which of the following would provide the best synthesis of 3,5-dimethyl-2-hexanone? A) Ethyl acetoacetate + NaOC2H5 + CH3I; then KO-t-Bu + (CH3)3CCH2Br; then

NaOH; then H3O+; then heat B) Ethyl acetoacetate + NaOC2H5 + (CH3)3CBr; then KO-t-Bu + CH3I; then

NaOH; then H3O+; then heat C) Ethyl acetoacetate + NaOC2H5 + (CH3)2CHCH2Br; then KO-t-Bu + CH3I;

then NaOH; then H3O+; then heat D) Ethyl acetoacetate + NaOC2H5 + (CH3)2CHCH2CHBrCH3; then NaOH; then

H3O+; then heat E) Ethyl acetoacetate + NaOC2H5 + CH3I; then KO-t-Bu + (CH3)2CHBr; then

NaOH; then H3O+; then heat Ans: C

Page 724: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 37. Which of the following would provide the best synthesis of 3-ethyl-6-methyl-2-

heptanone? A) Ethyl acetoacetate + NaOC2H5 + CH3CH2I; then KO-t-Bu +

(CH3)3CCH2CH2Br; then NaOH; then H3O+; then heat B) Ethyl acetoacetate + NaOC2H5 + (CH3)3CCH2Br; then KO-t-Bu + CH3CH2I;

then NaOH; then H3O+; then heat C) Ethyl acetoacetate + NaOC2H5 + (CH3)2CHCH2CH2Br; then KO-t-Bu +

CH3CH2I; then NaOH; then H3O+; then heat D) Ethyl acetoacetate + NaOC2H5 + (CH3)2CHCH2CH2CHBrCH2CH3; then

NaOH; then H3O+; then heat E) Ethyl acetoacetate + NaOC2H5 + CH3CH2I; then KO-t-Bu + (CH3)2CHCH2Br;

then NaOH; then H3O+; then heat Ans: C

Topic: Synthesis

38. Which of the following would afford the best synthesis of diethyl phenylmalonate,

C2H5O

O

OC2H5Ph

O

A)

C2H5O

O

OC2H5

O

Na+..BrPh +

B)

OC2H5

OPh C2H5O

O

OC2H5

NaOC2H5C2H5OH

H3O+

+

C) O

OC2H5Ph C2H5O

OOC2H5

O

NaOC2H5C2H5OH

H3O+

+

D)

O

OC2H5Ph

O

OC2H5

NaOC2H5C2H5OH

H3O+

D. +

E)

H

O

OC2H52CHOPh

NaOC2H5C2H5OH

H3O+

+

Ans: B

Page 725: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 39. What product is formed during the following reaction?

i. NaOC2H5, C2H5OHii. HOAc

IV

I II

V

Ph

O

OC2H5

O

OC2H5

Ph

OOC2H5

OPh

O

OC2H5

O

O

OO

Ph Ph OC2H5

OH O

III

Ph

O

O

+

A) I B) II C) III D) IV E) V Ans: B

Topic: Synthesis

40. Which compound may be prepared using a Mannich reaction?

IV

I II

V

N

O

III

CO2H O CO2Et

CO2Et

O O

N

O

A) I B) II C) III D) IV E) V Ans: C

Page 726: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 41. Which compound could be prepared using a Michael reaction?

IV

I II

V

HO

O OIII

O

OC2H5

O O

O

OC2H5

O OO

A) I B) II C) III D) IV E) V Ans: C

Topic: Synthesis

42. Which compound could be prepared via Dieckmann condensation?

IV

I II

V

HO

O O

III

O

OC2H5

O O

O

O

O OO

A) I B) II C) III D) IV E) V Ans: D

Page 727: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 43. Which reagents would you use to prepare the following substance from ethyl

acetoacetate?

Ph

O O

A)

i) NaH/DMSO; ii) PhCOCl; iii) OH−/H2O, heat; iv) H3O+; v) heat

B) i) NaOEt/EtOH; ii) PhCOCH2Br; iii) OH−/H2O, heat; iv) H3O+; v) heat

C) i) heat; ii) NaOEt/EtOH; iii) PhCOCH2Br

D) i) NaOEt/EtOH; ii) PhCl

E) i) NaOEt/EtOH; ii) PhCOCl; iii) OH−/H2O, heat; iv) H3O+; v) heat

Ans: A

Topic: Synthesis 44. Which of the following statements is true about the anion formed from the reaction of

diethyl malonate with sodium ethoxide? A) It can react with an ∝, β-unsaturated ester by conjugate addition. B) It can condense with aldehydes and ketones. C) It can be alkylated with an alkyl halide. D) It is resonance stabilized. E) All of the above statements are true. Ans: E

Page 728: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 45. Which reagents would be used in a Mannich reaction to synthesize

OO

H(CH3)2NHI + +

OO

H(CH3)3NII + +

O

(CH3)3NIII + +

OH O

H(CH3)2NHIV + +

O

(CH3)2NHV +

N

O

base

A) I B) II C) III D) IV E) V Ans: D

Page 729: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 46. What combination of reagents can be used to make the following substance via an

enamine?

O

ONH+ +I

II

III

IV

O

O

O

ONH

O

OCl NH

O

ONH2

+ +

+ +

+ +

A) I B) II C) III D) IV E) Both reactions II and III Ans: C

Topic: Synthesis

47. Which organic reagents would you need to make 2-ethylpentanoic acid from diethyl malonate? A) Bromoethane, 1-bromopropane, sodium ethoxide, and potassium tert-butoxide B) 3-Bromohexane and sodium ethoxide C) 3-Bromopentane and sodium ethoxide D) Bromoethane, 2-bromopropane, sodium ethoxide, and potassium tert-butoxide E) 2-Bromopentane and sodium ethoxide Ans: A

Page 730: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 48. Which organic reagents would you need to make 2-ethylheptanoic acid from diethyl

malonate? A) Bromoethane, 1-bromopentane, sodium ethoxide, and potassium tert-butoxide B) 3-Bromooctane and sodium ethoxide C) 3-Bromoheptane and sodium ethoxide D) 1-Bromopropane, 2-bromopentane, sodium ethoxide, and potassium tert-butoxide E) 2-Bromoheptane and potassium tert-butoxide Ans: A

Topic: Synthesis

49. 2-Methylcyclohexane-1,3-dione can be synthesized from:

I

II

O

OEt

O

IV

V

O

OEt

O

O

OEt

O

O

O

O

III

CH3MgBr H3O+

KMnO4, OH−

i. NaOEtii. H3O+

i. NaOEtii. H3O+

i. NaOEtii. H3O+

A) I B) II C) III D) IV E) V Ans: C

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Chapter 19

Topic: Synthesis 50. 2-Heptanone can be synthesized by which reaction sequence?

A)

CH3(CH2)3Br i. dil.OH−

ii. H3O+heatEthyl acetoacetate NaOEt

EtOH

B)

heat CH3(CH2)3BrEthyl acetoacetate NaOEtEtOH

C)

i. dil.OH−

ii. H3O+heat CH3(CH2)3BrEthyl acetoacetate NaOEt

EtOH

D)

CH3(CH2)3Br i. dil.OH−

ii. H3O+heatEthyl acetoacetate

E)

i. NaOEt, EtOHii. CH3COCl

i. dil.OH−

ii. H3O+heatEthyl hexanoate

Ans: A

Topic: Synthesis 51. Consider the synthesis below: What is compound X?

CO2Et i. NaOEt, EtOHii. H3O+

CO2EtCO2Et

+ X

A) O=C(OEt)2 B) HCO2Et C) EtO-CO-CO-OEt D) CH3CO2Et E) BrCH2CO2Et Ans: A

Topic: Synthesis

52. Consider the synthesis above. What is compound Y?

CO2EtCO2Et CO2Et

1) KOt-Bu2) "Y"

1) NaOH/H2O, heat

2) H3O+

3) heat (− CO2) A) BrCH2CO2Et B) EtO-CO-CO-OEt C) CH3CH2Br D) C6H5CH2Br E) C6H5Br Ans: D

Page 732: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 53. Consider the synthesis below. What is compound Z?

CO2Et

III

EtO2C CO2Et

CO2EtEtO2C CO2EtOI II

IV V

EtO2C CO2Et

CO2EtCO2Et CO2Et

1) KOt-Bu2) "Y"

1) NaOH/H2O, heat

2) H3O+

3) heat (− CO2)

"Z"

A) I B) II C) III D) IV E) V Ans: B

Page 733: 45669583 Organic Practice

Chapter 19

Topic: Synthesis 54. The Knoevenagel condensation of p-methoxybenzaldehyde with ethyl acetoacetate in

the presence of diethylamine produces which of these?

CO2Et

MeO O

I

MeO

OHCO2Et

O

II

OMeO

EtO2C

O

III

MeO

OCO2EtO MeO

OCO2Et

IV V A) I B) II C) III D) IV E) V Ans: A

Topic: Synthesis

55. What alkylating agent would be used with 2-phenylethanal in the Corey-Seebach method for the preparation of 4-methyl-1-phenyl-2-pentanone? A) Isopropyl bromide B) Butyl bromide C) sec-Butyl bromide D) Isobutyl bromide E) tert-Butyl bromide Ans: D

Topic: Synthesis

56. What alkylating agent would be used with 2-phenylethanal in the Corey-Seebach method for the preparation of 6-methyl-1-phenyl-2-heptanone? A) 1-bromo-4-methylpentane B) 2-bromo-4-methylpentane C) 1-bromo-6-methylheptane D) 1-bromo-5-methylhexane E) None of the above could be used Ans: A

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Chapter 19

Topic: General Information 57. Which of the following statements is true of the enamine,

N:

A) The enamine can be made from cyclohexanone + pyrrolidine. B)

It has another resonance structure : N

:

+

C) It can be acylated at the ∝-carbon of the original carbonyl compound. D) It can be alkylated. E) All of the above are true. Ans: E

Topic: General Information

58. Which of the following statements is true of the following enamine?

N:

A) The enamine can be made from cyclopentanone + pyrrolidine. B)

It has another resonance structure: N

:

+

C) It can be acylated at the ∝-carbon of the original carbonyl compound. D) It can be alkylated. E) All of the above are true. Ans: E

Topic: General Information

59. In the synthesis of barbiturates (general structure shown below), the R groups would originate in which step?

HN

NH

O

O O

R'R

A) Alkylation of the unsubstituted barbituric acid B) Alkylation of the urea C) Alkylation of the starting diethyl malonate D) Alkylation of an enamine E) Alkylation via a Grignard reagent Ans: C

Page 735: 45669583 Organic Practice

Chapter 19

Topic: General Information 60. Which of these is not a reversible process?

A) Base-promoted ester hydrolysis B) Acid-catalyzed ester hydrolysis C) Aldol addition D) Claisen condensation E) Acetal formation Ans: A

Topic: General Information

61. The Claisen condensation of which of these esters demands the use of (C6H5)3CNa as the base (as opposed to sodium ethoxide)? A) CH3CH2CO2C2H5 B) CH3CO2C2H5 C) C6H5CH2CO2C2H5 D) C6H5CH(CH3)CO2C2H5 E) None of these Ans: D

Topic: General Information

62. The Claisen condensation of which of these esters demands the use of (C6H5)3CNa as the base (as opposed to sodium ethoxide)? A) CH3CH2CH2CO2C2H5 B) CH3CH2CO2C2H5 C) C6H5CH2CH2CO2C2H5 D) (CH3)2CHCH2CO2C2H5 E) None of these Ans: E

Topic: General Information

63. Which of these halides is predicted to alkylate malonic ester (as the anion) in highest yield? A) CH3I B) C6H5Br C) (CH3)3CCH2Cl D) CH3CHClCH3 E) All of these should be equally effective. Ans: A

Page 736: 45669583 Organic Practice

Chapter 19

Topic: General Information 64. The Claisen condensation produces which of these?

A) An ∝-keto ester B) A β-keto ester C) A β-hydroxy ester D) A β-hydroxyaldehyde E) A β-diketone Ans: B

Topic: General Information

65. Cyclization reactions, such as the Dieckmann condensation, are best carried out using fairly dilute solutions of the compound to be cyclized. Why is this so? A) It then is possible to use less base. B) The reagents generally are expensive. C) A smaller amount of the compound to be cyclized can be used. D) Intermolecular condensation is minimized at low concentration. E) The concentration factor is unimportant. Ans: D

Topic: General Information

66. Why is CH3ONa not used in the Claisen condensation of ethyl acetate? A) CH3O- is a weaker base than the CH3CH2O- which is used. B) CH3O-Na+ is more difficult to prepare than CH3CH2O-Na+. C) CH3O- would abstract a proton from the ethyl group of the ester. D) Use of CH3O-Na+ would result in transesterification. E) CH3O-Na+ can be used as well as CH3CH2O-Na+. Ans: D

Topic: General Information

67. Which of these combinations is not one which would result in the formation of essentially one Claisen condensation product when one compound is added slowly to the mixture of the other and the base employed? HCO2Et + CH3CH2CO2Et A)

HCO2Et + CH3CH2CO2Et B) PhCO2Et + CH3CO2Et C) (CO2Et)2 + PhCH2CO2Et D) (CH3)3CCO2Et + CH3CO2Et E) PhCH2CO2Et + CH3CO2Et Ans: E

Page 737: 45669583 Organic Practice

Chapter 19

Topic: General Information 68. Which structure represents an ester enolate?

I II III III

O

O

O

O

O

O

O

O

A) I B) II C) III D) IV E) Both B) and C) Ans: E

Topic: General Information

69. Which of these amines is/are used with aldehydes and ketones to form enamines?

I II III III

HN

NHN

N

A) I B) II C) III D) IV E) Both I and II Ans: E

Topic: General Information

70. Which base is employed in the alkylation of ethyl pentanoate with methyl iodide? A) Sodium methoxide B) Sodium ethoxide C) Sodium hydride D) Potassium tert-butoxide E) Lithium diisopropylamide Ans: E

Topic: General Information

71. Which base is employed in the alkylation of methyl hexanoate with ethyl iodide? A) Sodium methoxide B) Sodium ethoxide C) Sodium hydride D) Potassium tert-butoxide E) Lithium diisopropylamide Ans: E

Page 738: 45669583 Organic Practice

Chapter 19

SHORT ANSWER QUESTIONS

Topic: General Information 72. Compounds having two carbonyl groups separated by an intervening carbon atom are

called ____________. Ans: β-dicarbonyl compounds

Topic: Active hydrogens

73. The pKa for protons on the carbon between two carbonyls is about 9-11. This greater acidity (as compared to single carbonyl systems) can be accounted for by ______________. Ans: resonance delocalization of the negative charge over two carbonyls rather than

just one

Topic: Claisen condensation 74. Esters frequently react in the presence of alkoxides by a reaction called the __________

condensation. Ans: Claisen

Topic: Dieckmann condensation

75. An intramolecular Claisen condensation is known as a _____________. Ans: Dieckmann condensation

Topic: General Information

76. When planning a reaction with an ester and an alkoxide ion, it is important to use an alkoxide that has the same alkyl group as the ester in order to avoid ________________.Ans: transesterification

Topic: Synthetic Strategy

77. The ethyl acetoacetate anion is the synthetic equivalent of the ___________. Ans: acetone enolate

Topic: Malonic Ester synthesis

78. A reaction of a particular β-dicarbonyl compound that gives substituted or disubstituted acetic acids is called the _____________. Ans: malonic ester synthesis

Topic: Active Hydrogen compounds

79. Compounds with two electron-withdrawing groups attached to the same carbon atom are known as ____________ or _____________. Ans: active hydrogen compounds; active methylene compounds

Topic: Synthetic Strategy

80. “Umpolung” is a German term meaning __________. Ans: polarity reversal

Page 739: 45669583 Organic Practice

Chapter 19

Topic: Knoevenagel Condensation 81. An aldol-type condensation between an active methylene compound and an aldehyde or

ketone is called a _____________. Ans: Knoevenagel condensation

Topic: Synthetic Strategy

82. In Chapter 16 we learned an efficient method for the crossed aldol condensation using lithium diisopropylamide as the base. This was specific for forming the kinetic enolate in ketones. If we instead wished to access the thermodynamic enolate instead, what method should we use? Ans: The Stork enamine synthesis; convert the ketone to the enamine, which will form

the more highly substituted double bond and act as a synthetic equivalent for the thermodynamic enolate.

Topic: General Information

83. Physiologically speaking, barbiturates are very effective __________. Ans: soporifics or sleep-inducers

Topic: Claisen Condensation

84. Explain why ethyl 2-methylpropanoate does undergo the usual Claisen condensation. Ans: In order for Claisen condensation to occur efficiently, there must be at least 2

hydrogen atoms alpha to the ester group. Although only one hydrogen appears to be substituted during the reaction, a second alpha hydrogen must originally be present, otherwise the overall reaction has an unfavorable equilibrium.

Topic: Dieckmann Condensation

85. Explain why diethyl pentanedioate does undergo a Dieckmann condensation. Ans: Dieckmann condensation of diethyl pentanedioate would afford a four-membered

ring. This ring is expected to have a considerable degree of ring strain and can account for the observed lack of reactivity.

OO

OO

O

O

O

Topic: Dieckmann Condensation

86. Predict what is likely to happen when ethyl 6-oxooctanoate is treated with NaOEt, followed by acid work-up. Ans: A cyclization similar to Dieckmann condensation is likely to occur, giving 2-

propanoylcyclopentanone as the major product: O

OO

O

O

Page 740: 45669583 Organic Practice

Chapter 19

Topic: Acylation of Active Hydrogen Compounds 87. Explain why acylation of active methylene compounds must be carried out in aprotic

solvents, typically using NaH to generate the enolate anion: why can sodium ethoxide/ethanol not be used in these reactions? Ans: Acylating agents such as acyl halides and acid anhydrides would react rapidly

with ethanol to form esters; also, during this process, the ethoxide ion would be neutralized. NaH/aprotic solvent bypasses these issues and affords the expected products in good yields.

Topic: 1,3-Dithiane Reactivity

88. Explain how the reactivity of 1,3-dithianes is different from that of the aldehydes from which they are typically prepared. Ans: The carbonyl carbon of an aldehyde is partially positive and thus, reacts with

nucleophiles. By contrast, upon conversion into a dithiane and subsequent treatment with butyllithium, this same carbon becomes negatively charged, and reacts with electrophiles. This phenomenon is described as “umpolung”.

Topic: Multistep Reaction Sequence:

89. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

CO2Et

CO2Et

BrBri. NaH ii.iii. NaOEtiv. NaOH, heatv. H3O+, heat

?

Ans:

CO2Et

CO2Et

CO2Et

CO2EtBr

Na+ −:CO2Et

CO2Et NaH Br Br

CO2H CO2EtCO2Et

NaOEt

i. NaOH, heatii. H3O+, heat

Page 741: 45669583 Organic Practice

Chapter 19

Topic: Multistep Reaction Sequence: 90. What is the final product of the following reaction sequence? Give structural details of

all significant intermediates. O NH

O

O

i. , p-TsOH

ii. , EtOH, reflux

iii. H2O

?

Ans: O NH N

O

O

OO

H2O

N

O

Br

p-TsOH

:

+

O

EtOH, reflux

O

Topic: Multistep Reaction Sequence: 91. What is the final product of the following reaction sequence? Give structural details of

all significant intermediates. O NH

Br O

O

i. , p-TsOH

ii.

iii. H2O

?

Ans: O NH N Br O

O

O

OO

H2O

N

O O

Brp-TsOH

:

+

Page 742: 45669583 Organic Practice

Chapter 19

Topic: Multistep Reaction Sequence: 92. What is the final product of the following reaction sequence? Give structural details of

all significant intermediates.

O

O

O

Bri. Zn,

ii. NH4Cliii. PCCiv. t-BuOK, t-BuOHv. CH3I

?

Ans:

O

OBr

O

O

O

O

Oi. Zn,

ii. NH4Cl

i. t-BuOK, t-BuOHii. CH3I

OH

OO

O

O

PCC

Topic: Multistep Reaction Sequence: 93. What is the expected final product when phenylacetonitrile is subjected to the following

reaction sequence?

CN ?i. EtO-, EtOH

ii. CH3CH2IAns:

CN CNi. EtO-, EtOH

ii. CH3CH2I

Page 743: 45669583 Organic Practice

Chapter 19

Topic: Multistep Reaction Sequence: 94. What is the final product of the following reaction sequence? Give structural details of

all significant intermediates.

OO ?

i. Cl2, FeCl3

ii. , EtO-, EtOH

O

OAns:

O O

Cl

O

O

Cl

Cl2, FeCl3 EtO-, EtOH

O O O

O

O

Topic: Synthetic Strategy

95. Suggest a reasonable synthetic strategy to carry out the following transformation.

O2N

O

O O2N OH NO2

OH

Ans:

O2N

O

O O2N O

O O

NO2

O2N OH NO2

OH

EtO-, EtOH

i. LAHii. H2O

Page 744: 45669583 Organic Practice

Chapter 19

Topic: Synthetic Strategy 96. Suggest a reasonable synthetic strategy to carry out the following transformation.

Br

O

O Br O Br Ans:

Br

O

O Br O

O O

Br

Br O Br

EtO-, EtOH

H3O+, heat

O OH

Br O Br

Topic: Multistep Reaction Sequence

97. What is the final product of the following reaction sequence? Give structural details of all significant intermediates.

i. EtO-, EtOH

ii. H3O+

iii. NaBH4, H2O

?O

OO

O

Ans: i. EtO-, EtOHii. H3O+ O

O OHO

O O

O

OO

O

NaBH4 H2O

Page 745: 45669583 Organic Practice

Chapter 19

Topic: Multistep Reaction Sequence 98. What is the final product of the following reaction sequence? Give structural details of

all significant intermediates.

i. NaH, DMF

ii. CH3CH2COCl

iii. NaOH, H2O

iv. H3O+, heat

?O

O O

Ans:

i. NaH, DMFii. CH3CH2COCl

O O

O

O

O O OO

O

i. NaOH, H2O

ii. H3O+, heatO

OH

OO

Topic: Reaction Products

99. Suggest a reasonable synthetic strategy for the synthesis of 3-heptanone from propanal. Ans: O SHHS

H3O+S

S

i. n-BuLiii. I

S

SHgCl2 CH3OH, H2O

O

3-heptanone

propanal

Page 746: 45669583 Organic Practice

Chapter 19

Topic: Reaction Products 100. Suggest a reasonable mechanism for the following reaction.

O

O

O

OO

O i.EtONa, EtOH, 25oCii. H3O+

+

O

O

OO

O

O

Ans:

O

O

OO

O

O

EtO

O

OO

O

H3O+

O

O

OO

O

O

O

O

EtOH + :−

::

..

..:−

−..

: :

: :

O

O

OO

O

O

O

OO

OH+

: .. :

Page 747: 45669583 Organic Practice

Chapter 20

747

MULTIPLE CHOICE QUESTIONS

Topic: Nomenclature 1. Which of these is an acceptable alternative name to "(1-methylbutyl)amine"?

A) 2-Aminopentane B) 2-Pentanamine C) Isopentylamine D) sec-Pentylamine E) Both A) and B) Ans: E

Topic: Nomenclature

2. Which is a correct common name for the following substance?

N

A) Ethylethylisobutylamine B) Diethylisobutylamine C) sec-Butyldiethylamine D) Ethylethyl-sec-butylamine E) 2-Diethylaminobutane Ans: C

Topic: Nomenclature

3. Which of the following is a tertiary amine? A) CH3CH2CH2CH2NH2 B) CH3CH2NHCH2CH(CH3)2 C) (CH3CH2)2NCH2CH(CH3)2 D) (CH3CH2)4N+ OH- E) (CH3CH2)3CNH2 Ans: C

Topic: Nomenclature

4. What type of amine is N-methyl-2-methyl-3-hexanamine? A) Primary B) Secondary C) Tertiary D) Quaternary E) None of these Ans: B

Page 748: 45669583 Organic Practice

Chapter 20

748

Topic: Nomenclature 5. Which of these is properly termed a "quaternary ammonium salt"?

A) (CH3)3CCH2CH2NH3+ Cl−

B) (CH3CH2CH(CH3)CH2)2NH2+ Cl−

C) (CH3CH2CH2)3NH+ Cl− D) (CH3CH2CH2)4N+ Cl− E) None of these Ans: D

Topic: Chemical Tests and Separations

6. Which reagent would serve as the basis for a simple chemical test that would distinguish between the pair of compounds listed below?

NH2HN

and

A) AgNO3 in H2O B) Dilute NaHCO3 C) Dilute NaOH D) C6H5SO2Cl/OH-, then H3O+ E) Dilute HCl Ans: D

Topic: Chemical Tests and Separations

7. Which reagent would serve as the basis for a simple chemical test that would distinguish between the pair of compounds listed below?

NH2 NH2and

A) AgNO3 in H2O B) HONO, 0-5°C then β-naphthol C) Dilute NaOH D) C6H5SO2Cl and OH- in H2O E) Dilute HCl Ans: B

Topic: Chemical Tests and Separations

8. Which reagent will distinguish between C6H5NH2 and (C6H5)2NH? A) HCl (aq) B) NaOH C) C6H5SO2Cl/OH-, then H3O+ D) Br2/CCl4 E) KMnO4 Ans: C

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Chapter 20

749

Topic: Chemical Tests and Separations, Nomenclature

9. Which reagent will distinguish between 2-amino-2,3-dimethylpentane and 1-amino-3-methyl-2-pentene? A) HONO, 0-5°C B) C6H5SO2Cl/OH-, then H3O+ C) NaOH D) HCl E) Br2/CCl4 Ans: E

Topic: Chemical Tests and Separations, Nomenclature

10. Which reagent could be used to separate a mixture of aniline and toluene? A) KMnO4 in H2O B) Dilute NaOH C) Dilute NaHCO3 D) Ag(NH3)2OH E) Dilute HCl Ans: E

Page 750: 45669583 Organic Practice

Chapter 20

750

Topic: Chemical Tests and Separations 11. Compound W has the molecular formula C11H17N. Treatment of W with

benzenesulfonyl chloride in base gives no reaction. Acidification of the resulting mixture gives a clear solution. The 1H NMR spectrum of W consists of: triplet, δ 1.0 quartet, δ 2.5 singlet, δ 3.6 (2H) multiplet, δ 7.3 (5H) The most likely structure for W is: A) N

H

B) N

C)

N

D) N

E)

N

Ans: B

Topic: Chemical Tests and Separations

12. Which of these could be resolved into separate enantiomers? A) 4-methyl-1-pentanamine B) 4-methyl-2-pentanamine C) N-methyl-1-butanamine D) N,N-dimethyl-1-propanamine E) N-Butyltrimethylammonium bromide Ans: B

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Chapter 20

751

Topic: Reaction Products 13. What final product is expected from the following reaction sequence?

IV

II

V

IIICl

Br

Br Cl

NO2

Br

Cl

NOBr

HO2P

Cl

PO2HBr

Br

Cl

OHBr

Cl

NO2

I

i. Fe/HCl

ii. NaHCO3

iii. Br2/H2O

iv. HONO, 0-5oC

v. H3PO2

?

A) I B) II C) III D) IV E) V Ans: B

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Chapter 20

752

Topic: Reaction Products 14. What compound is likely to be obtained via the following reaction sequence?

IVII V

BrBrCl Br BrBrBr

PO2H

ClBr

NO2

BrBr

Cl

Br

Br

NO2

BrNH2

IIII

?

i. HONO, 0-5oC

ii. CuCl

iii. Fe/HCl

iv. NaOH, H2O

v. HONO, 0-5oC

vi. H3PO2

A) I B) II C) III D) IV E) V Ans: C

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Chapter 20

753

Topic: Reaction Products 15. What would be the product, L, of the following reaction?

Cl

IV

II

V

CNNH

NH2

III

NH2

I

i. NaCNii. H2, Ni

?

A) I B) II C) III D) IV E) V Ans: E

Topic: Reaction Products

16. What final product is expected when toluene is subjected to the following reaction sequence? i) KMnO4, NaOH; ii) H3O+ ( product = C7H6O2); iii) SOCl2; iv) NH3 (product = C7H7NO); v) Br2, NaOH A) C6H5CONH2 B) C6H5CH2NH2 C) p-CH3C6H4SO2NH2 D) p-CH3C6H4NH2 E) C6H5NH2 Ans: E

Page 754: 45669583 Organic Practice

Chapter 20

754

Topic: Reaction Products 17. What would be the product of the following reaction sequence?

IV

I II

V

III

Cl

O

ON O

N

OH

N

N

N

i) , AlCl3 ii) (CH3)2NHiii) LiBH3CN

?

A) I B) II C) III D) IV E) V Ans: C

Page 755: 45669583 Organic Practice

Chapter 20

755

Topic: Reaction Products 18. What would be the product of the following reaction sequence?

IVII

NN

OH

N

N

III

N

I

?i. CH3Iii. Ag2O, H2Oiii. heat

A) I B) II C) III D) IV E) Answers A) and C) only Ans: A

Topic: Reaction Products

19. Which product could not be formed during the following reaction?

IV

I II

V

III

NH2

OHOH

HO OH

HONO0-5oC

?

A) I B) II C) III D) IV E) V Ans: E

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Chapter 20

756

Topic: Reaction Products 20. What would be the product of the following reaction sequence?

IVII V

Br

NO2

PO2H

NOBr

PO2H

Cl

Br BrBr BrOHBr

NO2

IIII

?

i. Fe/HCl

iv. NaOH, H2O

iii. Br2/H2O

v. HONO, 0-5oC

vi. H3PO2

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

21. Identify the compound (Z) formed when aniline is subjected to the following series of reactions: i.) NaNO2, H2SO4, dil.H2SO4 0-5oC; ii) Cu2O, Cu(NO3)2 , H2O A) C6H5NH2 B) C6H5Cl C) C6H5OH D) C6H6 E) None of these Ans: C

Topic: Reaction Products

22. Which is the predominant product formed when m-dinitrobenzene is treated with H2S/NH3 ? A) m -HSC6H4NH2 B) m -C6H4(NH2)2 C) m -HOC6H4NH2 D) m -H2NC6H4NO2 E) C6H5NH2 Ans: D

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Chapter 20

757

Topic: Reaction Products 23. Which is the major product of the following reaction?

IV

I II

V

III

NH2

OH NO2

OH

NN

OH NN

HO

?i. HONO, 0-5oCii. , NaOH

OH

2 A) I B) II C) III D) IV E) V Ans: E

Topic: Reaction Products

24. What is the final product? OH

C7H9Ni. Fe/HClii. OH−

i. Br2(excess)ii. H2O

product

i. HONO, 0-5oC

ii. H2O, Cu2O,

Cu(NO3)2

Final Product A) 2-Bromo-4-methylaniline B) 2,6-Dibromo-4-methylaniline C) 2,6-Dibromo-4-methylphenol D) 2,4-Dibromophenol E) 3,5-Dibromotoluene Ans: C

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Chapter 20

758

Topic: Reaction Products 25. What is the final product, C?

O

O

O

OHO

NH2

I II

H2N

O

CO2− NH2

−O2C

III

H3O+C4H7NO3

O−O2C

NH2

Br

IV

Br2

OH−C

V

N-Br

O

O

NH3excess NH4

++ C4H5NO3−

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

26. What would be the product of the following reaction sequence?

Br

i) KMnO4, NaOH, heat

ii) H3O+

iii) PCl5iv) NaN3

v) heat

vi) H2O

?

A) p-bromobenzamide B) p-bromobenzaldehyde oxime C) p-bromobenzenesulfonamide D) p-bromoaniline E) 4-bromo-3-chlorobenzoic acid Ans: D

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Chapter 20

759

Topic: Reaction Products 27. What is the final product of the following sequence of reactions?

O2N

NO2

Final productH2S, NH3EtOH

i. HONO, 5oCii. KI

C6H6N2O2

A) 1-Iodo-3-nitrobenzene B) 3-Nitroaniline C) 3-Nitrophenol D) 3-Nitrosoaniline E) 3-Nitrosophenol Ans: A

Topic: Reaction Products

28. When an equimolar mixture of ammonia and butyl bromide reacts, which of these products will form? A) Butylamine B) Dibutylamine C) Tributylamine D) Tetrabutylammonium bromide E) All of these Ans: E

Topic: Reaction Products

29. What is the chief alkene product when butylethylmethylpropylammonium hydroxide is heated to 150°C? A) CH2=CH2 B) CH3CH=CH2 C) CH3CH2CH=CH2 D) E-CH3CH=CHCH3 E) Z-CH3CH=CHCH3 Ans: A

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Topic: Synthesis 30. Which of the following reactions would yield C6H5CH2NH2?

A)

Br i. NaCNii. LiAlH4, etheriii. H2O

B) ONH3H2, Ni

C)

i. NaN3ii. LiAlH4, etheriii. H2O

Br

D) All of these E) Answers B) and C) only Ans: E

Topic: Synthesis

31. Which of the following reaction sequences would yield aniline? A)

i. HNO3, H2SO4ii. Fe, HCliii. NaOH, H2O

B)

Oi. NH3

ii. Br2,OH−

Cl

C)

i. NH3 (excess)

ii. HONO, 0-5oC, ether

iii. H3PO2

Br

D) All of the above E) Answers A) and B) only Ans: E

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Topic: Synthesis 32. Which of the following might be used to synthesize m-bromoaniline?

A)

i. HNO3, H2SO4ii. Fe, HCliii. NaOH, H2O iv. Br2, H2O

B)

O

Cli. Br2, FeBr3 ii. HNO3, H2SO4iii. H2, Pt

C)

i. Br2, FeBr3ii. SOCl2iii. NH3iv. Br2, NaOH

OOH

D) Answers A) and B) E) Answers B) and C) Ans: C

Topic: Synthesis

33. The best synthesis of 3,5-dibromotoluene would be: A) Toluene, Br2, Fe and heat B) p-CH3C6H4NH2, Br2, H2O; then HONO, 0-5°C; then H3PO2 C) Toluene, fuming HNO3, H2SO4; then NH3, H2S; then HONO, 0-5°C; then CuBr D) m-Dibromobenzene, CH3Cl, AlCl3, heat E) m-Bromotoluene, HNO3, H2SO4; then NH3, H2S; then HONO, 0-5°C; then CuBr Ans: B

Topic: Synthesis

34. The best synthesis of m-dibromobenzene would be: A) Benzene, Br2, FeBr3, heat B) Aniline, Br2, H2O; then HONO, 0-5°C; then CuBr C) Nitrobenzene, HNO3, H2SO4, heat; then Fe/HCl (excess); then 2 HONO, 0-5°C;

then 2 CuBr D) Bromobenzene, HNO3, H2SO4; then Fe, HCl, C2H5OH, reflux; then HONO, 0-

5°C; then CuBr E) Answers C) and D) Ans: C

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Topic: Synthesis 35. The best synthesis of m-fluoronitrobenzene would be:

A) Nitrobenzene, fuming HNO3, H2SO4, heat; then NH3, H2S; then HONO, 0-5°C; then HBF4; then heat

B) Aniline, F2, heat C) Fluorobenzene, HNO3, H2SO4, heat D) o-Nitroacetanilide, NH3, H2S; then Br2, OH-; then HF E) m-C6H4(NH2)2, HONO, 0-5°C; then CuNO2; then HBF4 Ans: A

Topic: Synthesis

36. Which is the best preparation of benzonitrile, C6H5CN, from benzene? A) HNO3; then Fe/HCl; then HONO, 0-5°C; then CuCN B) CH3I, AlCl3; then hot KMnO4; then H3O+; then SOCl2; then NH3; then NaOH +

Cl2 C) CH3I, AlCl3; then Br2, hν; then KCN D) Br2, Fe; then KCN E) CH3I, AlCl3; then Br2 (2 eq.), hν; then hot NaOH; then HCN Ans: A

Topic: Synthesis

37. Which of the following can be used to prepare 2-aminopentane (pure)?

KOH NH2NH2

C2H5OH

I. (1mol) 2-bromopentane + (1mol) NH3

II. (1mol) 2-bromopentane + (1mol) NaN3

III. Phthalimide

LAHEt2O

2-bromopentane

A) I B) II C) III D) I and II E) II and III Ans: E

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Topic: Synthesis 38.

Which is the best method to prepare

NH2

? A) O

NH3(excess)H2, Ni

B)

BrNH3

C)

CH3NH2H2, NiO

D)

NO2 NH2 HONO 0-5oC

+

E)

hνH2, Ni

+ HNO3

Ans: A

Topic: Synthesis 39.

Identify the best method(s) to prepare

HN

. A) NH2 (1 mol)

(1 mol)CH3I

B) O

(CH3)2NHH2, Ni

C)

OCH3NH2H2, Ni

D) A) and B) E) B) and C) Ans: C

Topic: Synthesis, Nomenclature

40. Your task is to convert o-xylene into o-diaminobenzene. Which sequence of reagents constitutes the best method? A) NaNH2 and heat B) NBS/CCl4; then NH3; then Br2/OH- C) KMnO4, OH-, heat; then H3O+; then PCl5; then NH3, then Br2/OH- D) KMnO4, OH-, heat; then H3O+; then SOCl2; then NH3; then LiAlH4; then Br2/OH- E) KMnO4, OH-, heat; then H3O+; then NH3 with H2/Ni Ans: C

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Topic: Synthesis

41. How would one carry out the following transformation: ?

Cl

?

ClH2NA) NaNO2,HCl, 0-5°C; then HNO3 B) NaNO2,HCl, 0-5°C; then H3PO2 C) NaNO2,HCl, 0-5°C; then H2,Ni D) C6H5SO2Cl, OH-; then HCl E) NaH, DMSO Ans: B

Topic: Synthesis

42. How could one carry out this synthesis? O OH

Br

?NH2

Br A) SOCl2; then NH3; then H3PO2 B) CH3Li, ether; then NH3, H2, Ni C) SOCl2; then NH3; then Br2, NaOH D) PCl5; then NH3; then HCl, NaNO2, 0-5°C E) PCl5; then CH3NH2; then KMnO4, OH-, heat Ans: C

Topic: Synthesis

43. Consider the synthesis below. What is reagent A? NO2

B

NH2BrBrA C

A) Br2, FeBr3 B) Fe, HCl; then OH− C) NH2Cl, AlCl3 D) H3PO2 E) LiNH2 Ans: B

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Topic: Synthesis 44. Consider the synthesis below. What is compound B?

NO2

B

NH2BrBrA C

IV

II

V

III

Br BrNH2

BrNH2

BrNO2

Br

NO2Br

I

A) I B) II C) III D) IV E) V Ans: C

Topic: Synthesis

45. Consider the synthesis below. What is reagent C? NO2

B

NH2BrBrA C

A) excess Br2, H2O B) Fe, HCl; then OH- C) NH2Cl, AlCl3 D) CuBr E) HNO3, H2SO4, Fe Ans: A

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Topic: Synthesis 46. Consider the synthesis below. What is reagent A?

NH2BrBr

CNBrBri. HCl, NaNO2

ii. "A"

A) H3PO2 B) HCN C) P4O10 D) CuCN E) CuCl2 Ans: D

Topic: Synthesis

47. What reagent can effect the following transformation? CN

BrBrCO2H

BrBr?

A) CO2; then H3O+ B) H3O+, heat C) Mg; then CO2; then H3O+ D) LiAlH4, ether E) KMnO4, OH-, heat; then H3O+ Ans: B

Topic: Synthesis

48. What reagent can effect the following transformation? CO2H

BrBrCO2H

CO2H

BrBr?

A) CO2; then H3O+ B) H3O+, heat C) Mg; then CO2; then H3O+ D) H2O2, heat E) KMnO4, OH-, heat; then H3O+ Ans: E

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Topic: Synthesis 49. What reagent can effect the following transformation?

NO2

NO2

NO2

NH2

?

A) Fe/HCl; then OH- B) H2S, NH3, C2H5OH C) H2, Ni, high pressure D) Zn(Hg)/HCl E) Raney Ni Ans: B

Topic: Synthesis

50. Consider the synthesis below. What is reagent “Z”? NO2

NH2

NO2

Cl

i. HONO, 0-5oCii. "Z"

A) CuCl B) CuCl2 C) NaCl D) KCl E) HCl/heat Ans: A

Topic: Synthesis

51. What reagent can effect the following transformation? NO2

Cl

NH2

Cl

?

A) Fe/HCl; then OH- B) NH2Cl C) H3PO2 D) CuCN E) HONO, then NH3 Ans: A

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Topic: Synthesis 52. Consider the following reaction: what is the expected product?

IV

II

V

IIICl

Br BrCl

NH2

NH2

Cl

BrNH2

Cl

Br

I

Br

H2N Cl

NH2Br Br

Br

Br

NH2

Cl

Br2, H2O ?

A) I B) II C) III D) IV E) V Ans: B

Topic: Synthesis

53. Consider the synthesis below. What is reagent “Y”? NH2

Cl Cl

Br Bri. HONO, 0-5oCii. "Y"

Br Br

A) Br2/FeBr3 B) CuBr C) CuBr2 D) H3PO2 E) H3PO4 Ans: D

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Topic: Synthesis 54. What is the chief product of the Hofmann elimination reaction applied to the compound

shown?

NOH

IV

II

V

IIII

A) I B) II C) III D) IV E) V Ans: A

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Topic: Synthesis 55. What is the principal product when aniline is treated with sodium nitrite and

hydrochloric acid at 0-5°C and this mixture is added to p-ethylphenol?

IV

II

V

III

OH OH

HO

N

OH

N

I

OH

NN

N

N

A) I B) II C) III D) IV E) V Ans: A

Topic: Synthesis

56. What is the final product in the Curtius rearrangement of the acyl azide formed from butanoyl chloride?

II III

IV V

NH2NH2 N C O

NH

O

N3

O

I

A) I B) II C) III D) IV E) V Ans A

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Topic: Synthesis 57.

Which combination of reactants will not produce HN ?

A)

NH

Oi. LiAlH4, etherii. H2O

B)

HN

Oi. LiAlH4, etherii. H2O

C)

H2NO + NaBH3CN

D)

H2N+O NaBH3CN

E)

HN

O

Br2, NaOH

Ans: E

Topic: Synthesis 58. The overall conversion RBr ⎯⎯⎯⎯→ RCH2NH2 can be accomplished by

successive application of which of these sets of reagents? A) Mg, ether; then NH3 B) NaN3; then LiAlH4, ether C) NaCN; then LiAlH4, ether D) H2C=O; then NH3 E) H2NOH; then LiAlH4, ether Ans: C

Topic: Synthesis

59. Which would be a good method to synthesize m-nitroaniline? A) 1,3-Dinitrobenzene + H2S and NH3 in EtOH B) Aniline + HNO3/H2SO4 C) Aniline + CH3COCl; then HNO3/H2SO4 D) Nitrobenzene + NH3 and AlCl3 E) More than one of the above Ans: A

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Topic: Basicity 60. Which of the following compounds would be the strongest base?

II III

IV V

I

NH2

ONH2

NH2

O2N

NH2 NH2

A) I B) II C) III D) IV E) V Ans: B

Topic: Basicity

61. Which of the following compounds would be the strongest base?

NH2

II III

IV V

I

NH

N

NOH

N

O

A) I B) II C) III D) IV E) V Ans: D

Topic: Basicity

62. Which would be the weakest base? A) p-Methylaniline B) p-Methoxyaniline C) Hexylamine D) p-Nitroaniline E) Dipropylamine Ans: D

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Topic: Basicity 63. Arrange the following amines in order of decreasing basicity in aqueous solution:

NH3 CH3CH2CH2NH2 (CH3CH2CH2)2NH (CH3CH2CH2)3N I II III IV A) IV > III > II > I B) III > II > IV > I C) I > IV > II > III D) II > III > I > IV E) III > I > II > IV Ans: B

Topic: Basicity

64. In aqueous solution, which of the following (as the conjugate acid) possesses the smallest value for pKa? A) C6H5NH2 B) NH3 C) (CH3CH2)3N D) (CH3CH2)2NH E) CH3CH2CH2NH2 Ans: A

Topic: Basicity

65. Which of these is the strongest acid?

II III

IV V

I

NH3

I

NH3

NH3

O2N

NH3

NH3

A) I B) II C) III D) IV E) V Ans: B

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Topic: Basicity 66. Which of these is the strongest acid?

II III

IV V

NH2

O

I

NH

O

N

O

NH

O O

NH3

A) I B) II C) III D) IV E) V Ans: D

Topic: Basicity

67. Which of these compounds is soluble in dilute sodium hydroxide solution?

II III

IV V

I

NH

O

O

NH

O

SN

O O

NH

HN

A) I B) II C) III D) IV E) V Ans: A

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Topic: Reactive Intermediates and General Considerations 68. Which is not an intermediate in the Hofmann degradation reaction?

RCONH2 RNH2KOHBr2

A) RN=C=O B)

R NHBr

O

C)

R NBr

O....

D)

HO NH

OR

E)

R N

OBr

Br Ans: E

Topic: Reactive Intermediates and General Considerations

69. Which of these compounds is expected to possess the lowest boiling point? A) CH3CH2CH2CH2CH2NH2 B) CH3CH2CH2NHCH2CH3 C) (CH3CH2)2NCH3 D) (CH3CH2)2CHOH E) (CH3)3CCH2NH3

+ Cl- Ans: C

Topic: Reactive Intermediates and General Considerations

70. This type of compound is the only one of these which can be converted by reduction into a 1°, 2° or 3° amine, according to its particular structure: A) Nitrile B) Oxime C) Azide D) Amide E) Nitroalkane Ans: D

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Topic: Reactive Intermediates and General Considerations 71. When the aromatic -NH2 group is to be converted to an -OH group via a diazonium salt,

the nitrous acid used is generated in situ by the reaction of a nitrite salt with which acid?A) HCl B) HBr C) HNO3 D) H2SO4 E) CH3CO2H Ans: D

Topic: Reactive Intermediates and General Considerations

72. The reaction of which of these compounds with nitrous acid results in a stable N-nitroso compound? A) C6H5NH2 B) C6H5N(CH3)2 C) CH3CH2CH2CH2CH2NH2 D) C6H5NHCH3 E) CH3CH2CONH2 Ans: D

Topic: Reactive Intermediates and General Considerations

73. When the process ArNH2 ⎯⎯⎯⎯→ ArY is carried out via an intermediate diazonium salt, this salt is isolated only in the case in which Y is which of these groups?A) -F B) -Cl C) -Br D) -I E) -CN Ans: A

Topic: Reactive Intermediates and General Considerations

74. What is the basis for the successful resolution of racemic C6H5CHOHCO2H through use of the chiral amine, C6H5CH(NH2)CH3? A) One enantiomer is more soluble than the other. B) The racemic mixture is converted into a single isomer in the basic solvent. C) The diastereomeric salts formed have different solubilities. D) The diastereomeric salts have different boiling points. E) The diastereomeric salts have different melting points. Ans: C

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Topic: Reactive Intermediates and General Considerations 75. Which of these alkyl halides cannot be used effectively in a Gabriel amine synthesis?

A) 1-bromopentane B) 1-bromo-3-methylbutane C) 2-bromo-3-methylpentane D) 1-bromo-2,3-dimethylbutane E) 2-bromo-2,3-dimethylbutane Ans: E

SHORT ANSWER QUESTIONS

Topic: Stereochemistry 76. If the three alkyl groups of a tertiary amine are all different, the amine will be chiral. In

practice, however, it is virtually impossible to separate the two enantiomers, because they interconvert rapidly through a process called _________________. Ans: nitrogen inversion

Topic: Relative Basicity

77. In solution, two factors affect the relative basicity of amines. These factors are: __________________. Ans: electron donation by alkyl substituents and stabilization of the alkylaminium ion

by hydrogen bonding with solvent

Topic: Relative Basicity 78. Arylamines are less basic than alkylamines because of _______________.

Ans: delocalization of the lone pair on nitrogen into the aromatic system

Topic: Enantiomer Resolution 79. Explain how an enantiomerically pure amine can be used to resolve racemic forms of

acidic compounds. Ans: The amine reacts with the acidic compound to form a pair of diastereomeric salts,

which can be easily separated.

Topic: General 80. ______________ is used in automotive airbags.

Ans: Sodium azide

Topic: General, Synthesis of Amines 81. There are two very versatile synthetic methods that can be used to synthesize primary,

secondary, and tertiary amines. These methods are: __________________. Ans: reductive amination of aldehydes and ketones, and reduction of amides

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Topic: Chemical Analysis 82. While primary amines react with nitrous acid to generate diazonium salts, secondary

amines react with nitrous acid to produce _____________. Ans: N-nitrosoamines

Topic: UV-Vis Absorption

83. Azo compounds are usually intensely colored because _________________. Ans: the N=N linkage brings two aromatic rings into conjugation, giving an extended π

system that generally absorbs in the visible region

Topic: General 84. Chemicals that inhibit the growth of microbes are called ______________.

Ans: antimetabolites

Topic: Hofmann Elimination 85. Eliminations that follow the Hofmann Rule tend to give the ______________ alkene as

the major product. Ans: least-substituted

Topic: Nomenclature

86. Draw the structure corresponding to the following name: (4Z,3S)-2,4,7-trimethyl-3-amino-4-octene Ans:

H2N H

Topic: Nomenclature 87. Draw the structure corresponding to the following name:

(3S,6R)-6-(2,4-dinitrophenyl)-3-amino-1-heptyne Ans: H2N

CH3H

NO2

NO2

H

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Topic: Exhaustive Methylation, Hofmann Degradation, Nomenclature 88. Before modern spectroscopic methods were developed, structures of many complex

amines were elucidated by examining the products obtained during Hofmann elimination of their quaternary ammonium hydroxides. The typical procedure involved the following steps, repeated as necessary, depending on whether the amine was primary, secondary or tertiary, until the final product was nitrogen-free: i) CH3I (excess); ii) Ag2O, H2O; iii) heat. What product(s) is (are) likely to be formed if 3,4-dimethylpiperidine is subjected to the above procedure? Ans: The reaction sequence would need to be repeated twice to obtain a nitrogen-free

product, since the starting compound is a secondary amine. The final product expected is 2,3-dimethyl-1,4-pentadiene along with trimethylamine.

NH

CH3I (excess) N I N

heatN

i. CH3I (excess)ii. Ag2O, H2Oiii. heat

N +

OHAg2O H2O

Topic: Multistep Reaction Sequence 89. What final product is likely when cyclohexene is subjected to the following reaction

sequence? Give structural details of all significant intermediates. i.) H3O+, H2O; ii) PCC; iii) (CH3)2NH; iv) NaBH3CN Ans: OH

PCCO N OH

NaBH3CNN

H3O+

H2O

(CH3)2NH

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Topic: Multistep Reaction Sequence 90. What final product is likely when p-dinitrobenzene is subjected to the following reaction

sequence? Give structural details of all significant intermediates. i.) H2S, NH3, EtOH; ii.)CH3CH2COCl; iii.) LiAlH4; iv) H2O Ans:

NO2

NO2

NO2

NH2

CH3CH2COCl

NO2

HN

NO2

HN OH2S, NH3EtOH

i. LiAlH4, Et2Oii. H2O

Topic: Multistep Reaction Sequence, Nomenclature 91. What final product is likely when acetophenone is subjected to the following reaction

sequence? Give structural details of all significant intermediates. i) Br2, FeBr3; ii) CH3CH2CH2NH2 ; ii.) NaBH3CN Ans:

O

Br

O

CH3CH2CH2NH2

N

Br

NH

Br

Br2FeBr3

NaBH3CN

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Topic: Gabriel Synthesis 92. Outline the steps involved in the Gabriel synthesis of 3-amino-2-methylpentane.

Ans:

NH

O

O

KOHN K

O

O

Br

NHNH

O

O

N

O

O

NH2

NH2NH2EtOHreflux

+

3-amino-2-methylpentane

Topic: Synthesis, Hofmann Rearrangement

93. Outline the steps involved in the synthesis of 4-bromo-3-nitro-aniline from 4-bromobenzaldehyde Ans: i. HNO3, H2SO4 ; ii) KMnO4, OH-, H2O; iii) H3O+; iv) SOCl2; v) NH3

vi) Br2, OH- O

Br

O

BrNO2

NH3

O

BrNO2

NH2NH2

BrNO2

Br2, NaOH

O

BrNO2

OH

O

BrNO2

Cl

SOCl2

i. KMnO4, OH−, H2O

ii. H3O+

4-bromo-3-nitro-aniline

4-bromobenzaldehyde

HNO3H2SO4

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Topic: Synthetic Strategy 94. Outline the steps involved in the synthesis of 4-bromo-3-nitro-phenol from 4-

bromobenzoic acid Ans: i) HNO3,H2SO4 ; ii) SOCl2; iii) NH3; iv) Br2, OH-; iv) NaNO2, H3O+, 0-5oC

v) Cu2O, Cu(NO3)2, H2O

Br2 NaOH

O

BrNO2

NH2

NH2

BrNO2

NH3

O

BrNO2

Cl

N2+

BrNO2

SOCl2

O

BrNO2

OH

HNO3H2SO4

OH

BrNO2

O

Br

OH

4-bromobenzoic acid

NaNO2, H3O+

0-5oCCu2O, Cu(NO3)2 H2O

4-bromo-3-nitro-phenol

Topic: Synthesis, Nomenclature 95. Outline the steps involved in the synthesis of 3-chloro-4-fluorophenyl acetate from 4-

aminoacetophenone Ans: i) Cl2, FeCl3; ii) NaNO2, H3O+, 0-5oC; iii) HBF4; iv) heat ; v) MCPBA

O

NH2

Cl2 FeCl3

O

NH2

Cl

O

FCl

O

N2+Cl

O

FCl

O

i. HBF4 ii. heat

4-aminoacetophenone

NaNO2, H3O+

0-5oC

3-chloro-4-fluorophenyl acetate

MCPBA

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Topic: Synthesis, Nomenclature 96. What is the principal product when p-toluidine is treated with sodium nitrite and

hydrochloric acid at 0-5°C and this mixture is added to o-ethylphenol? Ans:

NH2 N2+NaNO2, HCl

0-5oC

N

OH

N

OH

p-toluidine

Topic: Relative Base Strength

97. Explain why cyclohexylamine is a stronger base than aniline Ans: There are two major reasons for the observed difference in basicity between the

two substances: i) In aniline, the electron pair on N is delocalized over the aromatic ring

through resonance: this has the effect of decreasing the electron density at the nitrogen atom, relative to cyclohexylamine, in which no such resonance delocalization can occur, leading to lower base strength for aniline.

ii) In cyclohexylamine, the N atom is attached to an sp3 carbon, while in aniline the N atom is attached to an sp2 carbon: an sp2 carbon typically exerts a stronger electron-withdrawing effect, effectively decreasing the electron density on the nitrogen atom, resulting in weaker base strength.

Topic: Product Analysis by NMR

98. You have just completed an experiment involving the reduction of m-nitrobenzoic acid with Fe/HCl. In order to determine if your reaction has worked as planned, you have obtained the 1H NMR of your crude product. What will you scrutinize the spectrum for, in order to help you make this assessment? Ans: The appearance of 2 new N-H signals, in the range of about 2-6 ppm will be

indicative of successful reduction of the –NO2 group to the –NH2 group. These signals are characteristically somewhat broad, and should disappear (or decrease markedly) if the spectrum is rerun with an added drop of D2O to the original sample prepared for obtaining the 1H NMR. The rest of the signals are likely to remain more or less similar, with some changes in chemical shift likely (probably upfield shifts), since the –NO2 group is electron-withdrawing, while the –NH2 group is electron-donating.

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MULTIPLE CHOICE QUESTIONS

Topic: Nomenclature 1. The common name for 4-methylphenol is which of these?

A) Catechol B) p-Cresol C) Resorcinol D) Hydroquinone E) p-Xylenol Ans: B

Topic: Nomenclature

2. The common name for 3-methylphenol is which of these? A) Catechol B) m -Cresol C) m-tolylol D) Hydroquinone E) p-Xylenol Ans: B

Topic: Nomenclature 3. The common name for 1,2-benzenediol is which of these?

A) Catechol B) m -Cresol C) Resorcinol D) Hydroquinone E) o-Xylenol Ans: C

Topic: Nomenclature 4. What is the systematic (IUPAC) name for

OH

OH A) m-Hydroxyphenol B) m-Dihydroxybenzene C) Resorcinol D) 1,3-dihydroxybenzene E) 1,3-Benzenediol Ans: E

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Topic: Nomenclature 5. What is the systematic (IUPAC) name for

OH

A) p-Hydroxyphenol B) p-Dihydroxybenzene C) Resorcinol D) 1,4-dihydroxybenzene E) 1,4-Benzenediol Ans: E

Topic: Nomenclature

6. What is the systematic (IUPAC) name for

OH

NO2 A) m-Hydroxy-p-nitrotoluene B) 3-Hydroxy-4-nitrotoluene C) 5-methyl-2-nitrophenol D) 3-methyl-2-nitrophenol E) 2-Hydroxy-4methylnitrobenzene Ans: C

Topic: Nomenclature

7.

What is the systematic (IUPAC) name for

OH

BrO

A) p-Hydroxy-m-bromoacetophenone B) m-bromo-p-hydroxypropiophenone C) 3-bromo-4-hydroxypropiophenone D) 2-bromo-4-propanoylphenol E) 2-hydroxy-5-propanoylbromobenzene Ans: D

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Topic: Nomenclature 8.

Which of the following is 5-bromo-3-methyl-1-naphthol?

IV

I II

V

III

OH

Br

OH

Br

OH

Br

HO

Br

OH

Br

A) I B) II C) III D) IV E) V Ans: B

Topic: Acid/Base 9. Which of the following phenols would have the largest pKa?

IV

II

V

III

F

OH

O2N

OH CH3

HO

OH

Cl

OH

I

A) I B) II C) III D) IV E) V Ans: C

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787

Topic: Acid/Base 10.

Which of the following phenols would have the smallest pKa?

IV

II

V

III

OH

OO

OH

NO2HO

O

NH2OH

HO

O

I

A) I B) II C) III D) IV E) V Ans: C

Topic: Acid/Base

11. Which of the following substances would have the smallest pKa?

IV

II

V

III

OH

OO

OH

NO2HO

O

NH2OH

HOOH

O

I

A) I B) II C) III D) IV E) V Ans: E

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788

Topic: Acid/Base 12. Which of the following compounds would you expect to be the strongest acid?

A) CH3OH B) C6H5CH2OH C) p-CH3C6H4OH D) C6H5OH E) p-NO2C6H4OH Ans: E

Topic: Acid/Base

13. Which compound would be most acidic? A) Cyclohexanol B) 1-Hexanol C) Phenol D) 4-Methylphenol E) 4-Chlorophenol Ans: E

Topic: Acid/Base

14. Which of the following would be the strongest acid?

IV

II

V

III

OH

HO

OH

F3C Br

OH

HO

CH3

I

A) I B) II C) III D) IV E) V Ans: D

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789

Topic: Acid/Base 15.

Which of the following would be the strongest acid?

IV

II

V

III

OH

O

OHOH

Br

O

SO3HOH

HOOH

I

A) I B) II C) III D) IV E) V Ans: D

Topic: Acid/Base

16. Which would be soluble in aqueous sodium bicarbonate? A) Benzoic acid B) 4-Methylphenol C) 2,4-Dinitrophenol D) More than one of these E) All of these Ans: D

Topic: Acid/Base

17. Which reagent will distinguish between C6H5OH and C6H5CH2OH? A) NaHCO3 (aq) B) NaOH (aq) C) H2SO4 D) A) and B) E) B) and C) Ans: B

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Topic: Acid/Base 18. Which reagent will distinguish between C6H5OCH3 and p-CH3C6H4OH?

A) NaOH (aq) B) NaHCO3 (aq) C) H2CrO4 D) A) and B) E) None of these Ans: A

Topic: Acid/Base

19. Which compound reacts most rapidly with CH3ONa?

IV

II

V

III

Br Br NO2

NO2

Br

O2N

NO2Br

O2N

Br

NO2

I

A) I B) II C) III D) IV E) V Ans: D

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791

Topic: Acid/Base 20. Which of these species is the strongest base?

IV

II

V

III

O O

H3C

O

Cl

O2N

O

I

O

I

A) I B) II C) III D) IV E) V Ans: B

Topic: Reaction Products

21. Indicate the correct product, if any, of the following reaction.

II III

HOBr

Br

HOBr

Br

HOBr

Br

IV

HO

Br

HBr

I A) I B) II C) III D) IV E) There is no net reaction. Ans: E

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792

Topic: Reaction Products 22. Refluxing anisole, CH3OC6H5, with excess concentrated HBr would yield which of

these product mixtures? A) C6H5Br + CH3OH B) C6H5OH + CH4 C) C6H5OH + CH3OH D) C6H5Br + CH3Br E) C6H5OH + CH3Br Ans: E

Topic: Reaction Products

23. What product(s) would you expect from the following reaction?

II III

F3CNH2

F3C NH2

NH2

F3C

ClF3C

I

NaNH2

NH3(l), -33oC

alone alonealone

A) I B) II C) III D) Substantial amounts of I and II E) Substantial amounts of I, II, and III Ans: B

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793

Topic: Reaction Products 24. What product(s) would you expect from the following reaction?

NO2

Br

O2N

II III

HO

NO2O2N

NaO

NO2O2N HO NH2

Br

I

?i. NaOH, NaHCO3,

H2O, heat

ii. H3O+

A) I B) II C) III D) Substantial amounts of I and II E) Substantial amounts of I, II, and III Ans: A

Topic: Reaction Products

25. What would be the major product of the following reaction?

II III

HO HO

Br

HO

Br

IV

HO

HO

I

Br2 (excess)H2O

Br

Br

Br

?

Br

A) I B) II C) III D) IV E) A mixture of I and II Ans: D

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794

Topic: Reaction Products 26. What products would you expect from the following reaction?

4-Chlorotoluenei. OH−/ H2O, 400oC

ii. H3O+?

A) 2-Methylphenol B) 3-Methylphenol C) 4-Methylphenol D) A) and B) E) B) and C) Ans: E

Topic: Reaction Products

27. What is the major product of the following reaction?

Phenoli) conc H2SO4,100oC

ii) HNO3 / H2SO4, heat

iii) H3O+/H2O, heat, steam distill

?

A) p-Hydroxybenzenesulfonic acid B) p-Nitrophenol C) o-Nitrophenol D) 4-Hydroxy-3-nitrobenzenesulfonic acid E) 2-Hydroxy-4-nitrobenzenesulfonic acid Ans: C

Topic: Reaction Products

28. Which products would be formed in the following reaction?

H3COCH3

conc HBr (excess) heat ?

A) Methoxybenzene + methyl bromide B) 2-Methylphenol + methyl bromide C) 2-Bromotoluene + methanol D) 2-Bromotoluene + methyl bromide E) Bromobenzene + methyl bromide Ans: B

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795

Topic: Reaction Products 29. What is the final product?

Phenol t-butyl chloride AlCl3

C10H14O(para-isomer)

i. NaOHii. CH3CH2I

?

A) 1-tert-Butyl-4-ethoxybenzene B) 1-tert-Butyl-4-ethylbenzene C) 1-tert-Butoxy-4-ethoxybenzene D) tert-Butyl ethyl ether E) 1-tert-Butoxy-3-ethylbenzene Ans: A

Topic: Reaction Products

30. What products(s) would you expect from the following reaction?

II IIII

NaNH2

NH3(l), -33oC?

H3CCl

H3C H3C H3CNH2

NH2alone alone alone

NH2

A) I B) II C) III D) Products I and II E) All of the above Ans: D

Topic: Reaction Products

31. What is the product of the following synthesis?

phenol1. H2SO4, 100oC

2. 2 equiv Br2, H2O

3. dil. H2SO4, heat

?

A) 2,3-Dibromophenol B) 2,4-Dibromophenol C) 2,6-Dibromophenol D) 2-Hydroxy-3,5-dibromobenzenesulfonic acid E) 2,4,6-Tribromophenol Ans: C

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796

Topic: Reaction Products 32.

What is the IUPAC name of the final product obtained via the following reaction sequence?

2-bromophenol 1. 2-bromopropane, AlCl32. NaOH3. (CH3CO)2O

?

A) 1-isopropyl-3-bromo-4-acetylbenzene B) 2-bromo-4-isopropyl -acetophenone C) 3-bromo-1-isopropyl-4-phenyl acetate D) (2-bromo-4-isopropyl)phenyl acetate E) None of the above correctly describes the product Ans: D

Topic: Reaction Products

33. What is the IUPAC name of the final product obtained via the following reaction sequence? 2-bromophenol 1. CH3I, base

2. Butanoyl chloride, AlCl33. Zn(Hg), HCl4. conc HBr, heat

?

A) 1-butanoyl-3-bromo-4-methoxybenzene B) 2-bromo-4-butylphenol C) 3-bromo-1-butyl-4-methoxybenzene D) 3,4-dibromo-1- butanoylbenzene E) None of the above correctly describes the product Ans: B

Topic: Reaction Products

34. What is the IUPAC name of the final product obtained via the following reaction sequence? 2-nitrophenol 1. H2, Ni

2. NaNO2, HCl, 0-5oC

3. KI

4. Br2, 5oC, CS2

?

A) 4-bromo-2-iodophenol B) 2-bromo-4-iodophenol C) 2,4-dibromophenol D) 2,4-dibromo-6- iodophenol E) 1-bromo-3-iodobenzene Ans: A

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797

Topic: Reaction Products 35.

What is the final product obtained via the following reaction sequence?

IV

II

V

III

OCH3

OH

OCH3

HO

BrH3CO

BrOH

HO

I

1-ethyl-4-methoxybenzene 1. NBS

2. Mg, Et2O

3. (CH3)2C=O

4. H3O+

5. conc HBr, heat

?

A) I B) II C) III D) IV E) V Ans: E

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798

Topic: Reaction Products 36. What product should be obtained if benzyne is generated in the presence of 1,3-

butadiene?

IV

II

V

IIII

A) I B) II C) III D) IV E) V Ans: A

Topic: Reaction Products

37. Which product is likely to be obtained during the following reaction of the isotope-labeled allyl ether (14C-isotopic site marked with an asterisk)?

O* ?

200oC

IV

II

V

III

OH

*

OH

*

OH

*

OH

*

O*

I

A) I B) II C) III D) IV E) V Ans: B

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799

Topic: Reaction Products 38. When sodium phenoxide is heated to 125°C with carbon dioxide under pressure and the

product mixture acidified, which of these is produced?

IV

II

V

III

HO

I

O

O

OH OH

OH

OHO OH

O

OH

O OOH OH

A) I B) II C) III D) IV E) V Ans: B

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800

Topic: Reaction Products 39. What product is likely to be obtained by the action of Ag+ or Fe+3 on the following

substance?

OHCH3

OH

?Ag+ or Fe3+

IV

II

V

III

O

O

O

O

CH3

OH

O

CH3

HO H

O

OH

O

O

OH

O

O

CH3

I

A) I B) II C) III D) IV E) V Ans: A

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801

Topic: Reaction Products 40. What is the product of the reaction of 1 mol of p-benzoquinone with 1 mol of isoprene

(2-methyl-1,3-butadiene)?

IV

II

V

IIIO

O

O

O

IO

O O

O

O

O

A) I B) II C) III D) IV E) V Ans: A

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Chapter 21

802

Topic: Reaction Products 41. What are the products of the reaction of phenol with propanoic anhydride in the

presence of base? O

O

O

O

IV

II IIII

O

O

O O

V

CH3CH2CO2− CH3CH2CO2

− CH3CH2CO2−

CH3CH2CO2− CH3CH2CH2OH

+ + +

+ +

A) I B) II C) III D) IV E) V Ans: C

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Chapter 21

803

Topic: Reaction Products 42. What is the product of the reaction of phenol and chloroacetic acid in basic solution,

followed by acidification?

IV

O

OCl OH

ClO

O

O

OH

OHOH

O

O OH

O

II

V

IIII

A) I B) II C) III D) IV E) V Ans: D

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Chapter 21

804

Topic: Reaction Products 43. Predict the product of this Cope rearrangement:

IV

C6H5

II

C6H5 C6H5

C6H5

I

C6H5

V

C6H5

III

180oC?

A) I B) II C) III D) IV E) V Ans: C

Topic: Reaction Products

44. What product is likely to be obtained when 1-bromo-2-nitrobenzene is heated with aqueous NaHCO3? A) 2-bromophenol B) 2-nitrophenol C) 2-bromophenyl carbonate D) 2-nitrophenyl carbonate E) Sodium 2-nitrophenoxide Ans: E

Topic: Reaction Products

45. What product is likely to be obtained when 1-chloro-3-nitrobenzene is heated with aqueous NaHCO3? A) 3-chlorophenol B) 3-nitrophenol C) 3-chlorophenyl carbonate D) Sodium 2-nitrophenoxide E) None of the above: no reaction is likely to occur Ans: E

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805

Topic: Reaction Products 46.

What product is likely to be obtained when 1-fluoro-2,4-dinitrobenzene is treated with sodium ethoxide? A) 2,4-dinitrophenol B) 1-ethoxy-2,4-dinitrobenzene C) 2,4-diethoxy-1-fluorobenzene D) 2,4-dinitrophenylsodium E) None of the above: no reaction is likely to occur Ans: E

Topic: Reaction Products

47. What product is likely to be obtained when 1-chloro-2-trifluoromethylbenzene is treated with sodium amide in liquid ammonia? A) 2-(trifluoromethyl)aniline B) 3-(trifluoromethyl)aniline C) 4-(trifluoromethyl)aniline D) 2-chloroaniline E) None of the above: no reaction is likely to occur Ans: B

Topic: Synthesis

48. Which of the following would provide a synthesis of aspirin, o-CH3COOC6H4COOH ? A) C6H5COOH, CH3COOH, AlCl3, heat; then H2O B) CH3COOC6H5, CO2, heat; then H3O+ C) CH3COOC6H5, HCOOC2H5, C2H5O-; then H3O+; then OH- D) C6H5OH, CO2, H3O+; separate isomers; then CH3COOH, AlCl3 E) C6H5OH, OH-, CO2, heat, pressure; then H3O+; then (CH3CO)2O Ans: E

Topic: Synthesis

49. Identify the commercial preparation(s) of phenol. A) Chlorobenzene + NaOH at 350°C; then H3O+ B) Benzene + O2 C) C6H5CH(CH3)2 + O2; then H3O+, heat D) A) and B) E) A) and C) Ans: E

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806

Topic: Synthesis 50. Which method could be used for preparing methoxybenzene from phenol?

A) NaOH, then CH3I B) NaOH, then CH3OSO2CH3 C) NaOH, then CH3OCH3 D) More than one of these E) All of these Ans: D

Topic: Synthesis

51. Which of these is an acceptable synthesis of phenetole (ethyl phenyl ether)? A)

Chlorobenzene CH3CH2ONa

100oC

B) Sodium phenoxideCH3CH2I

70oC

C) Sodium phenoxide(CH3CH2O)2SO2

100oC

D)

PhenolCH3CH2OH, H2SO4

70oC

E) More than one of these Ans: E

Topic: Synthesis

52. Which of the following reactions would yield p-tert-butylphenol? A)

Phenol + H3O+

B)

Phenol + OH H3O+

C)

Phenol + Cl AlCl3

D) All of these E) None of these Ans: D

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807

Topic: Synthesis 53. Which of these is a satisfactory method for the preparation of m-nitrophenol from

benzene? A)

i) HNO3 / H2SO4; ii) Sn / HCl; iii) NaNO2, H2SO4, H2O, 0-5oC; iv) Cu2O, Cu2+, H2O; v) HNO3

B)

i) Cl2, Fe; ii) HNO3 / H2SO4; iii) NaOH, H2O; iv) H3O+

C)

i) HNO3/H2SO4; ii) Cl2, Fe; iii) NaOH, H2O; iv) H3O+

D)

i) 2 HNO3 / 2 H2SO4; ii) NH3, H2S; iii) NaNO2, H2SO4, H2O, 0-5oC; iv) Cu2O, Cu2+, H2O

E)

i) HNO3 / H2SO4; ii) NaOH / fusion; iii) H3O+

Ans: D

Topic: Synthesis 54. Which of these reactions does not produce phenol?

A)

O

O

i. NaOH, H2O

ii. H3O+

B)

ONa H3O+

C)

O HI

D)

Cl H2O

100oCE) NH2 i. NaNO2, H2SO4, H2O, 0-5oC

ii. Cu2O, Cu2+, H2OAns: D

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808

Topic: Relative Reactivities and General Considerations 55. Which of the following would be most likely to undergo a nucleophilic substitution

reaction with aqueous sodium hydroxide by an addition-elimination mechanism?

IV

II

V

III

Br

Br

NO2

NO2

Br

OO

Br

NO2O2N

Br

I

A) I B) II C) III D) IV E) V Ans: D

Topic: Relative Reactivities and General Considerations

56. In terms of reactivity towards nucleophiles, bromobenzene is most similar to which of these? A) Allyl bromide B) Vinyl bromide C) tert-Butyl bromide D) Propyl bromide E) Methyl bromide Ans: B

Topic: Relative Reactivities and General Considerations

57. In nucleophilic aromatic substitution, the attacking species (the nucleophile) necessarily is: A) A Lewis base B) Neutral C) Positively charged D) Negatively charged E) Electron deficient Ans: A

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809

Topic: Relative Reactivities and General Considerations 58. Which of the following substances readily undergoes ring bromination with Br2, even in

the absence of a Lewis acid catalyst? A) 2,4-Dinitrotoluene B) 2,4-Dimethylbenzoic acid C) 3-Nitroaniline D) 4-Bromophenyl acetate E) 1,3-benzenediol Ans: D

Topic: Relative Reactivities and General Considerations

59. Which is the leaving group when the following substance reacts with sodium cyanide in DMSO solution?

Br

H

Br

HNO2

I

II

III

IV

V

A) I B) II C) III D) IV E) V Ans: A

Topic: Relative Reactivities and General Considerations

60. Which position is predicted to be the chief site of substitution when the following substance reacts with bromine in carbon disulfide at 10°C ?

HO CH3

IIIIII IV

V

A) I B) II C) III D) IV E) V Ans: A

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Chapter 21

810

Topic: Relative Reactivities and General Considerations 61. Which of these resonance structures makes the greatest contribution to the hybrid for the

intermediate in the SNAr reaction of o-chloronitrobenzene with methoxide ion?

IV

II

V

III

NH3CO Cl

O

ON

H3CO Cl

O

ON

H3CO Cl

O

O

NH3CO Cl

O

ON

H3CO Cl

O

O

I

A) I B) II C) III D) IV E) V Ans: E

Topic: Relative Reactivities and General Considerations

62. The formation of equal amounts of m-toluidine (m-aminophenol) and p-toluidine in the reaction of p-bromotoluene with sodium amide in liquid ammonia at -33°C suggests this species as the reaction intermediate:

IV

II

V

III

Br

NH2

Br NH2

I

A) I B) II C) III D) IV E) V Ans: D

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Chapter 21

811

Topic: Relative Reactivities and General Considerations 63. Phenol is less reactive than expected in Friedel-Crafts acylations for which of these

reasons? A) The acid chloride or anhydride hydrolyzes under the reaction conditions. B) The electronegativity of the -OH group reduces the reactivity of phenol. C) Interaction of the -OH group with AlCl3 forms a species less reactive than phenol.D) The reaction gives O-acylation only, resulting in an ester. E) The aromatic ring complexes with AlCl3 with a resulting decrease in phenol

reactivity. Ans: C

Topic: Spectroscopic Analysis

64. Thymol, isolated from thyme, has the following structure: OH

Which of the following types of signal is NOT expected to be observed in its NMR spectrum? A) singlet B) doublet C) triplet D) septet E) all of the above types of signals are expected to be observed Ans: C

Topic: Spectroscopic Analysis

65. Methyl salicylate, commonly found in topical muscle relaxants, has the following structure:

OH

O

O Which of the following signals is NOT expected to be observed in its NMR spectrum? A) Singlet at ~4 ppm (3H) B) Doublet at ~7 ppm (1H) C) Quartet at about 7 ppm (4H) D) Singlet at ~ 6 ppm (1H) E) Two of the above types of signals are not expected to be observed Ans: C

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812

Topic: Spectroscopic Analysis 66. Eugenol, isolated from cloves, has the following structure:

OH

O Which of the following signals is NOT expected to be observed in its NMR spectrum? A) Singlet at ~4 ppm (3H) B) Doublet at ~2.5 ppm (2H) C) Singlet at ~ 7 ppm (1H) D) Singlet at ~ 6 ppm (1H) E) All of the above types of signals are expected to be observed Ans: E

Topic: Structure Identification

67. Compound L has the molecular formula C11H16O. L is insoluble in water but dissolves in aqueous NaOH. The infrared spectrum of L shows a broad absorption band in the 3200-3600 cm-1 region; its 1H NMR spectrum consists of: triplet, δ 0.80 singlet, δ 1.2 (6H) quartet, δ 1.5 singlet, δ 4.5 (1H) multiplet, δ 7.0 (4H) The most likely structure for compound L is:

IV

II

V

IIIHO O

HOO

HOI

A) I B) II C) III D) IV E) V Ans: E

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Chapter 21

813

SHORT ANSWER QUESTIONS

Topic: Synthesis 68. The most important laboratory synthesis of phenols is by _______________.

Ans: hydrolysis of arenediazonium salts

Topic: Claisen, Cope Rearrangement 69. The Claisen and Cope rearrangements are two examples of a general class of reactions

called ___________. Ans: pericyclic reactions

Topic: General

70. The carbon-halogen bonds in aryl and vinyl halides are both __________ and _____________ than the corresponding bonds in alkyl halides. Ans: shorter; stronger

Topic: General, Nucleophilic Aromatic Substitution

71. Nucleophilic aromatic substitution reactions (SNAr) take place via a delocalized carbanion intermediate called a ______________. Ans: Meisenheimer complex

Topic: General, Nucleophilic Aromatic Substitution

72. Nucleophilic aromatic substitution reactions (SNAr) require three components: a good leaving group on the aromatic ring, a strong nucleophile, and ________________. Ans: an electron-withdrawing substituent ortho or para to the leaving group

Topic: General, Nucleophilic Aromatic Substitution

73. In general, there are two types of nucleophilic aromatic substitution mechanisms. These are: ______________. Ans: addition-elimination or SNAr; elimination-addition or benzyne

Topic: Benzyne Intermediate

74. Benzyne is a very unstable intermediate, because _____________. Ans: the two carbons involved in the extra π bond are sp hybridized, causing a severe

amount of bond angle distortion and strain

Topic: Nomenclature 75. The commonly used name for hydroxybenzene is __________.

Ans: phenol

Topic: Industrial Synthesis 76. Most of the worldwide industrial preparation of phenol is now based on the

___________. Ans: cumene hydroperoxide method

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Chapter 21

814

Topic: Industrial Synthesis 77. The cumene hydroperoxide synthesis of phenol is industrially very satisfying, because it

takes two inexpensive starting materials, ___________ and ___________, and converts them into two valuable products, phenol and __________. Ans: benzene; propene; acetone

Topic: Nomenclature

78. Draw the structure corresponding to the following IUPAC name: (2E,4S)-4-(3-hydroxyphenyl)-2-pentenoic acid Ans:

OH

O

H3C H

OH

Topic: Nomenclature 79. Draw the structure corresponding to the following IUPAC name:

(R)-2-Bromo-5-(3-methylpentyl)phenol Ans:

OHBr

H CH3

Topic: Nomenclature 80. Draw the structure corresponding to the following IUPAC name:

4-benzyl-3,5-diiodophenol Ans:

HO

I

I

Topic: Nomenclature 81. Give the IUPAC name of the following substance:

HO

H3C HO

O

Ans: (R)-methyl 6-(4-hydroxyphenyl)-4-methylhexanoate

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815

Topic: Relative Acidity 82. Draw the structure of the ionic species obtained when the following substance is treated

with NaOH: NH2 OH

HO Ans: NH2 O−Na+

HO

Topic: Chemical Analysis, Relative Acidity

83. Suggest a simple chemical test to distinguish between 4-methylphenol and 2,4,6-trinitrophenol, briefly explaining your rationale. Ans: Both substances will dissolve in aq NaOH via an acid-base reaction. However,

only 2,4,6-trinitrophenol, being significantly more strongly acidic, is likely to react with aq NaHCO3, releasing gaseous CO2 (easily observed as effervescence). The differences in reactivity can be attributed to the fact that nitro groups are strongly electron-withdrawing, while the methyl group is weakly electron- donating.

OH OH

NO2O2N

NO2

stronger acidgives CO2 with NaHCO3(aq)

weaker acidno reaction with NaHCO3(aq)

Topic: Reaction Product

84. Draw the structure of the product obtained when benzoquinone reacts with 2 molar equivalents of 1,3-butadiene via a Diels Alder reaction. Ans: O

O

+

O

O1 mol 2 mol

Diels AlderReaction

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816

Topic: Reaction Product 85. Draw the structure of the product obtained when the following substance is heated

strongly: O

Ans: O heat OH

(Claisen Rearrangement)

Topic: Reaction Product 86. Draw the structure of the final product obtained when 2-nitrophenol reacts with acetic

anhydride in presence of base. Ans:

OHNO2

O

O OO

NO2

Obase

Topic: Reaction Product 87. Draw the structure of the final product obtained when 1-chloro-2,4-dinitrobenzene is

heated with aqueous NaHCO3 at 100oC, followed by neutralization with H3O+ . Ans:

ClNO2

O2N

OHNO2

O2N

i. NaHCO3 (aq), 100oCii. H3O+

Topic: Reaction Product

88. Draw the structure of the final product obtained when 3-methylphenol is subjected to the following reaction sequence: i) NaOH; ii) CH3CH2CH2OSO2OCF3 Ans: OH O

i) NaOH ii) CH3CH2CH2OSO2OCF3

Topic: Reaction Sequence

89. Draw the structure of the final product obtained when 4-cyclopentylphenol is subjected to the following reaction sequence: i) NaOH; ii) CH3I; iii) NBS; iv) CH3ONa/CH3OH, heat Ans: i) NaOH

ii) CH3Iiii) NBSiv) CH3ONa, CH3OH, heat

OH O

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Chapter 21

817

Topic: Synthesis 90. The insecticide Sevin is synthesized from 1-naphthol and methyl isocyanate

(CH3-N=C=O). Draw the structure of this insecticide. Ans:

OH

+ CH3-N=C=O

O

O

NH

Sevin

Topic: Synthesis 91. Orange II is an azo dye made from 2-naphthol and the diazonium salt of p-

aminobenzenesulfonic acid. Indicate the synthetic steps involved in this synthesis and draw the structure of Orange II. Ans:

OH

SO3H

H2N

SO3H

−Cl+N2

OH

NN SO3H

NaNO2

H2SO4

0-5oC

OrangeII

Topic: Synthesis 92. Draw the structure of the product likely to be obtained from the reaction between

acetoacetic ester, bromobenzene and 2 molar equivalents of sodium amide (in liquid ammonia)? Briefly explain your rationale. Ans: This is likely to be a benzyne mediated (elimination-addition mechanism)

nucleophilic substitution reaction of bromobenzene. 1 equivalent of sodium amide is likely to promote elimination to form benzyne, while the 2nd equivalent of base would generate the anion of acetoacetic ester, which can then react with the benzyne to give the following product.

O

O O

Page 818: 45669583 Organic Practice

Chapter 21

818

Topic: Synthesis 93. Outline the steps involved in the synthesis of 3-bromo-4-methylphenol from 4-

nitrotoluene Ans: i. Br2, FeBr3 ; ii) Fe, HCl; iii) NaNO2, H2SO4, 0-5oC; iv) Cu2O, Cu2+, H2O

OH

Br

NO2

NO2

Br

NH2

Br

NO2FeHCl

Br2FeBr3

OH

Br

4-nitrotoluene 3-bromo-4-methylphenol

4-nitrotoluene i. NaNO2, H2SO4

0-5oC

ii. Cu2O, Cu2+,

H2O

3-bromo-4-methylphenol

Page 819: 45669583 Organic Practice

Chapter 21

819

Topic: Industrial Synthesis 94. A key step in the industrial synthesis of phenol from cumene is the oxidation of cumene

to cumene hydroperoxide with oxygen. Outline the mechanistic steps that lead to this oxidation product.

cumene cumene hydroperoxide

O OHO2

95-135oC

Ans: This is a radical chain reaction. A radical initiator is required to initiate the process, which begins with abstraction of the benzylic hydrogen to produce a 3o radical. The ensuing chain reaction leads to the formation of cumene hydroperoxide.

O-O ..

H

O O H O OH

O O

cumene

+ R . + R−H.

InitiationStep 1

PropagationStep 2

+

. .

. .

+ +

Step 3

cumene hydroperoxide

Page 820: 45669583 Organic Practice

Chapter 21

820

Topic: Industrial Synthesis 95. The industrial synthesis of phenol from cumene involves the acid hydrolysis of the key

intermediate, cumene hydroperoxide (formed from cumene via oxidation). Outline the mechanistic steps that lead to this oxidation product. Which other industrially important substance is produced as a by-product in this reaction?

cumene hydroperoxide

O OHH3O+

50-90oCOH

phenolAns: This is a hydrolytic rearrangement reaction. Protonation of the –OH group of

cumene hydroperoxide, leads to a 1,2-phenyl migration with concomitant loss of water. Nucleophilic addition to the resultant carbocation ultimately leads to the formation of phenol. Another industrially important substance, acetone, is formed as a by-product during this reaction, making this a doubly attractive synthetic strategy.

cumene hydroperoxide

O OHH3O+

50-90oCOH O+

phenol acetone

cumene hydroperoxide

O OH O OH2+- H2O

O+

H2O

OH2O+

OHO+

HHOO +

- H3O+

phenolacetone

H3O+

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Chapter 21

821

Topic: Synthesis 96. Suggest a reasonable synthetic strategy for the synthesis of 3-bromophenol from

acetophenone Ans: i) Br2, FeBr3; ii) MCPBA; iii) H3O+

Br2FeBr3

MCPBAO

O

O

Br

OH

Br

OH

Br

O

BrO

acetophenone 3-bromophenol

acetophenone H3O+

heat

3-bromophenol

Page 822: 45669583 Organic Practice

Chapter 21

822

Topic: Synthesis, Separation of (o-, p-) Products 97. When phenol is nitrated with dilute nitric acid, a mixture of o- and p- substituted

products is obtained. These products can then be separated by the technique of steam distillation. However, analogous products from the nitration of methoxybenzene cannot be similarly separated by steam distillation. Explain. Ans: In order for efficient separation of substances (from a mixture) by steam

distillation, there must be relatively large differences in volatility. The more volatile substance passes over with the steam, leaving the less volatile substance in the distillation flask. Differences in the volatility of the o- and p- nitrophenols may be predicted by considering hydrogen bonding effects: o-nitrophenol can exhibit intramolecular hydrogen bonding, while p-nitrophenol can exhibit intermolecular hydrogen bonding. Consequently, o-nitrophenol is likely to be significantly more volatile than p-nitrophenol, leading to the possibility of efficient separation by steam distillation. By contrast, since no hydrogen bonding is possible in the products obtained by nitration of methoxybenzene, there is no predictable difference in volatility. Hence, these products cannot be separated by steam distillation.

N OH

O

O

OCH3 OCH3

NO2

ONO

O

ONO

O

H

H

OCH3O2N

o-nitrophenolintramolecular hydrogen bondingmore volatile

p-nitrophenolintermolecular hydrogen bondingless volatile

+

no hydrogen bonding in either product:volatility differences not likely to be significant

methoxybenzene

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Chapter 21

823

Topic: Synthesis 98. Outline the steps involved in the synthesis of 3-nitrophenol from 1,3-dinitrobenzene

Ans: i) NH3, H2S, EtOH; ii) NaNO2, H2SO4, 0-5oC; iii) Cu2O, Cu2+, H2O

NO2

O2NNH3H2SEtOH

O2N

NO2

NH2

O2N

OH

O2N

OH

O2N

1,3-dinitrobenzene 3-nitrophenol

i) NaNO2, H2SO4, 0-5oC

ii) Cu2O, Cu2+, H2O

Topic: Synthesis, Hofmann/Curtius Rearrangement 99. Outline the steps involved in the synthesis of 3-nitrophenol from benzoic acid

Ans: i) HNO3, H2SO4 ; ii) SOCl2; iii) NH3; iv) Br2, NaOH; v) NaNO2, H2SO4, 0-5oC; vi) Cu2O, Cu2+, H2O or i) HNO3, H2SO4 ; ii) SOCl2; iii) NaN3; iv) heat; v) H2O; vi) NaNO2, H2SO4, 0-5oC; vii) Cu2O, Cu2+, H2O

Br2NaOH

NO2

NH2

O NH2

NO2

NH3

OH

O2N

O Cl

NO2

SOCl2

O OH

NO2

NO2

OH

CO2H

HNO3 H2SO4

O OH

benzoic acid 3-nitrophenol

i) NaNO2, H2SO4, 0-5oC

ii) Cu2O, Cu2+, H2O

3-nitrophenol

i) NaN3 ii) heatiii) H2O

Page 824: 45669583 Organic Practice

Chapter 21

824

Topic: Synthesis, Grignard Synthesis 100. Outline the steps involved in the synthesis of p-methoxybenzoic acid from phenol.

Ans: i) NaOH ; ii) CH3I; iii) Br2, FeBr3 ; iv) Mg, Et2O; v) CO2; vi) H3O+

OH

OH

O

Br2 FeBr3

O

Br

OH

OO

O

OHO

phenol p-methoxybenzoic acid

i) NaOHii) CH3I

i) Mg, Et2O

ii) CO2

iii) H3O+

(+ o- isomer)

Page 825: 45669583 Organic Practice

Chapter 22

825

MULTIPLE CHOICE QUESTIONS

Topic: Nomenclature, Definitions and Types of Carbohydrates 1. An aldaric acid is represented by:

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CO2HHHOHHO

I II III

OHHOHH

CO2H

CO2HHHOHHO

OHHOHH

CH2OH

CH2OHHHOHHO

IV

OHHOHH

CO2H

CHOHHOHHO

V A) I B) II C) III D) IV E) V Ans: C

Topic: Nomenclature, Definitions and Types of Carbohydrates

2. Epimers are represented by:

OHHOHH

CH2OH

CH2OHO

HHOOHHOHH

CH2OH

CHOOHHHHO

I II III

OHHOHH

CH2OH

CHOHHOHHO

HHOHHO

CH2OH

CHOOHHOHH

IV

HHOHHO

CH2OH

CHOHHOHHO

V A) I and II B) II and III C) I, II, and III D) III and IV E) I, II, and V Ans: B

Page 826: 45669583 Organic Practice

Chapter 22

826

Topic: Nomenclature, Definitions and Types of Carbohydrates 3. Which is a ketohexose?

A) D-Glucose B) D-Fructose C) D-Mannose D) D-Ribose E) (+)-Sucrose Ans: B

Topic: Nomenclature, Definitions and Types of Carbohydrates

4. Which of these compounds, I, II, III, IV, is a reducing disaccharide?

O H

OH HH

O

OH HH

O

HCH2OH

H

CH2OH

H

OH

OHHH

OH

OH

O H

OH HH

O

OHOH HO

HCH2OH

H H

OHHH

OH

OH

OH

OH HH

O

OH HO

OHCH2OH

H H

CH2OH

OHHH

OH

OH

CH2OH

H

I II

O H

OH HH

O

OCH3OH H

O

HCH2OH

H H

OHHH

OH

OH

CH2OH

H

III IV A) I alone B) II alone C) III alone D) IV alone E) I, II, III, and IV Ans: B

Page 827: 45669583 Organic Practice

Chapter 22

827

Topic: Nomenclature, Definitions and Types of Carbohydrates 5. Sugars that undergo mutarotation in neutral aqueous solution are:

O H

OH HH

O

OHOH HO

HCH2OH

H H

OHHH

OH

OH

CH2OH

H

V

O H

OH HH

O

OH HH

O

HCH2OH

H

CH2OH

H

OH

OHHH

OH

OHIV

O H

OH HH

OCH3

CH2OH

H

H

OH

OHIII

O H

OH HH

OH

CH2OH

H

H

OH

OHI

O OH

OH HH

H

CH2OH

H

H

OH

OHII

A) I and III B) III and IV C) II, III, and IV D) I and IV E) I, II, and V Ans: E

Topic: Nomenclature, Definitions and Types of Carbohydrates

6. Which of the following is an L-aldotetrose?

OHHOHH

CH2OH

CHOHHOOHH

CH2OH

CHO

I II III

OHHHHO

CH2OH

CHOOHHHHO

CH2OH

CO2H

IV

OHHHHO

CO2H

CH2OH

V A) I B) II C) III D) IV E) V Ans: C

Page 828: 45669583 Organic Practice

Chapter 22

828

Topic: Nomenclature, Definitions and Types of Carbohydrates 7. Which of the following is a D-aldotetrose?

OHHOHH

CH2OH

CHOHHOOHH

CH2OH

CO2H

I II III

OHHHHO

CH2OH

CHOOHHHHO

CH2OH

CH2OH

IV

HHOHHO

CH2OH

CHO

V A) I B) II C) III D) IV E) V Ans: A

Topic: Nomenclature, Definitions and Types of Carbohydrates

8. An aldonic acid is represented by:

OHHOHH

CH2OH

CO2HHHOHHO

OHHOHH

CH2OH

CH2OHHHOHHO

I II III

OHHOHH

CO2H

CO2HHHOHHO

OHHOHH

CO2H

CHOHHOHHO

IV

OHHOHH

CHO

CO2HHHOHHO

V A) I B) II C) III D) IV E) V Ans: A

Page 829: 45669583 Organic Practice

Chapter 22

829

Topic: Nomenclature, Definitions and Types of Carbohydrates 9. Which of the following is an L-aldopentose?

OHHOHH

CH2OH

CHOOHHHHO

CH2OH

CHOOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

CH2OH

CHOHHO

IV

HHOHHO

CH2OH

CH2OHCO

V A) I B) II C) III D) IV E) V Ans: B

Topic: Nomenclature, Definitions and Types of Carbohydrates

10. Which compound is D-galactose?

O H

OH HH

OH

CH2OH

OH

H

H

OHIII

O OH

H HH

H

CH2OH

OH

OH

H

OHI

O H

OH HH

OH

CH2OH

H

H

OH

OHII

O H

H HH

OH

CH2OH

H

OH

OH

OHIV

O H

OH OHH

OH

CH2OH

OH

H

H

HV

A) I B) II C) III D) IV E) V Ans: C

Page 830: 45669583 Organic Practice

Chapter 22

830

Topic: Nomenclature, Definitions and Types of Carbohydrates 11. Which of these is ∝-D-glucopyranose?

O OH

OH

CH2OH

OH

OHIII

O

OHOH

CH2OH

OH

OHI

O

OHOH

CH2OH

OH

OH

II

O OCH3

OHOH

CH2OH

OH

OHIV

O

OHOH

CH2OH

OH

OHV

A) I B) II C) III D) IV E) V Ans: A

Page 831: 45669583 Organic Practice

Chapter 22

831

Topic: Nomenclature, Definitions and Types of Carbohydrates 12. Which of these is a non-reducing monosaccharide?

O OH

OH

CH2OH

OH

OHIII

O

OHOH

CH2OH

OH

OHI

O

OHOH

CH2OH

OH

OH

II

O OCH3

OH

CH2OH

OH

OHIV

O

CH2OH

HOH2C OH

HO

OHV

A) I B) II C) III D) IV E) V Ans: D

Page 832: 45669583 Organic Practice

Chapter 22

832

Topic: Nomenclature, Definitions and Types of Carbohydrates 13. Which of these is a glycoside?

O OH

OH

CH2OH

OH

OHIII

O

OHOH

CH2OH

OH

OHI

O

OHOH

CH2OH

OH

OH

II

O OCH3

OH

CH2OH

OH

OHIV

O

OH

CH2OCH3

OH

OHV

OH

A) I B) II C) III D) IV E) V Ans: D

Page 833: 45669583 Organic Practice

Chapter 22

833

Topic: Nomenclature, Definitions and Types of Carbohydrates 14. Which are the anomers?

O OH

OH

CH2OH

OH

OHIII

O

OHOH

CH2OH

OH

OHI

O

OHOH

CH2OH

OH

OH

II

O

OH

CH2OH

OH

OHIV

OH

A) I and II B) I and III C) II and III D) II and IV E) III and IV Ans: B

Page 834: 45669583 Organic Practice

Chapter 22

834

Topic: Nomenclature, Definitions and Types of Carbohydrates 15. Consider the structures shown below. Which structure represents β-D-glucopyranose?

OHO

HO

OHOH

OH

OHO

HO

OHOH

OH

OHO

HOOH

OH

OH

OHO

OHOH

OH

OH

OHO

HOOH

OCH3

OH

I II

IVIII

VA) I B) II C) III D) IV E) V Ans: C

Page 835: 45669583 Organic Practice

Chapter 22

835

Topic: Nomenclature, Definitions and Types of Carbohydrates 16. Consider the structures shown below. Which compound is not a reducing sugar?

OHO

HO

OHOH

OH

OHO

HO

OHOH

OH

OHO

HOOH

OH

OH

OHO

OHOH

OH

OH

OHO

HOOH

OCH3

OH

I II

IVIII

VA) I B) II C) III D) IV E) V Ans: E

Topic: Nomenclature, Definitions and Types of Carbohydrates

17. Which of the following is the structure of D-galacturonic acid?

HHOOHH

CH2OH

CO2HOHHHHO

I II III

HHOOHH

CO2H

CHOOHHHHO

HHOOHH

CO2H

CO2HOHHHHO

IV

OHHHHO

CO2H

CHOHHOOHH

V

HHOOHH

CO2H

CH2OHOHHHHO

A) I B) II C) III D) IV E) V Ans: C

Page 836: 45669583 Organic Practice

Chapter 22

836

Topic: Nomenclature, Definitions and Types of Carbohydrates, Analysis

18. Which is not likely to give a brick-red precipitate with Benedict’s solution? A) Maltose B) Cellobiose C) Sucrose D) Lactose E) None of these Ans: C

Topic: Nomenclature, Definitions and Types of Carbohydrates 19. A glycoside is a compound which contains the structural features of these classes of

organic compounds: A) Aldehydes and alcohols B) Acetals and alcohols C) Hemiacetals and alcohols D) Ketones and alcohols E) Alcohols and carboxylic acids Ans: B

Topic: Nomenclature, Definitions and Types of Carbohydrates

20. Which of these is an example of a glucan? A) Maltose B) Sucrose C) Lactose D) Cellobiose E) Amylose Ans: E

Topic: Nomenclature, Definitions and Types of Carbohydrates

21. Which is a reducing sugar with an ∝-glycosidic linkage? A) Sucrose B) Maltose C) Lactose D) Cellobiose E) None of these Ans: B

Page 837: 45669583 Organic Practice

Chapter 22

837

Topic: Nomenclature, Definitions and Types of Carbohydrates 22. Which compound will not reduce Ag(NH3)2

+ ?

OHO

HOOH

OH

OCH3

I II

IVIII V

OHO

HOOH

OH

OO

HOOH

OH

OH

OHO

OHOH

OH

OH O

OH

HOH2C CH2OH

OH OH

CHO

OHH

CH2OH

A) I B) II C) III D) IV E) V Ans: A

Topic: Nomenclature, Definitions and Types of Carbohydrates

23. What is the correct description of this disaccharide?

O O OCH2OH CH2OH

A) The ∝-anomer of two D-glucose units joined by an ∝(1→4) linkage B) The ∝-anomer of two D-galactose units joined by an ∝(1→4) linkage C) The β-anomer of two D-galactose units joined by a β(1→4) linkage D) The β-anomer of two D-glucose units joined by a β(1→4) linkage E) The ∝-anomer of two D-galactose units joined by a β(1→4) linkage Ans: E

Page 838: 45669583 Organic Practice

Chapter 22

838

Topic: Nomenclature, Definitions and Types of Carbohydrates 24. What is a correct general description of the monosaccharide shown here?

O

CH2OH

HOH2C OH

OH OH A) The ∝-anomer of the pyranose form of an aldohexose B) The β-anomer of the pyranose form of an aldohexose C) The ∝-anomer of the furanose form of a ketohexose D) The β-anomer of the furanose form of a ketohexose E) The β-anomer of the furanose form of an aldohexose Ans: D

Topic: Nomenclature, Definitions and Types of Carbohydrates

25. What can be said, correctly, about a monosaccharide, the name of which is preceded only by (+) ? A) The compound is the ∝-anomer. B) The compound exists in the pyranose form. C) The compound is dextrorotatory. D) The compound has the same stereochemistry at the penultimate carbon as D-(+)-

glucose. E) The compound exists only in open-chain form. Ans: C

Topic: Nomenclature, Definitions and Types of Carbohydrates 26. How many stereoisomers of the L series would exist for the following pentose?

O=CHCHOHCHOHCHOHCH2OH A) 2 B) 3 C) 4 D) 5 E) 8 Ans: C

Page 839: 45669583 Organic Practice

Chapter 22

839

Topic: Reactions 27. Reaction of the following substance with sodium borohydride (NaBH4) would yield:

OHHOHH

CH2OH

CHOHHOHHO NaBH4

OHHOHH

CH2OH

CO2HHHOHHO

OHHOHH

CO2H

CO2HHHOHHO

I II III

OHHOHH

CH2OH

CH2OHHHOHHO

OHHOHH

CO2H

CHOHHOHHO

IV V

OHHOHH

CH2OH

CH3HHOHHO

?

A) I B) II C) III D) IV E) V Ans: C

Page 840: 45669583 Organic Practice

Chapter 22

840

Topic: Reactions 28. Reaction of the following substance with bromine water would yield:

OHHOHH

CH2OH

CHOHHOHHO Br2

H2O

OHHOHH

CH2OH

CO2HHHOHHO

OHHOHH

CO2H

CO2HHHOHHO

I II III

OHHOHH

CH2OH

CH2OHHHOHHO

OHHOHH

CO2H

CHOHHOHHO

IV

OHHOHH

CHO

CHOHHOHHO

V

?

A) I B) II C) III D) IV E) V Ans: A

Page 841: 45669583 Organic Practice

Chapter 22

841

Topic: Reactions 29. If J (below) were treated with dilute aqueous hydrochloric acid and the solution allowed

to stand, what compounds (other than methanol) would be formed in the solution?

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOHHOHHO

I II

O H

OCH3

CH2OH

OHHO

HH

HOH

H

dil HClH2O

O H

OH

CH2OH

OHHO

HH

HOH

H

III

O OH

H

CH2OH

OHHO

HH

HOH

H

IV

?

A) I and II B) I and III C) II and III D) I, III, and IV E) II, III, and IV Ans: D

Topic: Reactions 30. A compound X reacts with 3 mol of HIO4 to yield 2 mol of HCO2H and 2 mol of

HCHO. What is the structure of X?

I II III IV V

CHO

CHOH

CHOH

CHO

CH2OH

C

C

CH2OH

O

O

CHO

C

C

CHO

O

O

CHO

CHOH

CHOH

CH2OH

CH2OH

CHOH

CHOH

CH2OH

A) I B) II C) III D) IV E) V Ans: A

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Chapter 22

842

Topic: Reactions 31. A D-aldohexose, X, is subjected to a Ruff degradation. The degradation product is

treated with nitric acid to yield an optically inactive aldaric acid. A possible structure for X is:

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOOHH

CH2OH

CHOOHHHHO

IV

HHOHHO

CH2OH

CHOOHHHHO

V A) I B) II C) III D) IV E) V Ans: B

Topic: Reactions 32. Which of the following would yield D-glucose and D-mannose when subjected to a

Kiliani-Fischer synthesis?

OHHOHH

CH2OH

CHOHHO

OHHOHH

CH2OH

CHOOHH

I II III

OHHHHO

CH2OH

CHOOHH

HHOOHH

CH2OH

CHOOHH

IV

HHOOHH

CH2OH

CHOHHO

V A) I B) II C) III D) IV E) V Ans: A

Page 843: 45669583 Organic Practice

Chapter 22

843

Topic: Reactions 33. Reaction of the following substance with nitric acid would yield:

CHOHHOHHOOHHOHH

CH2OH

HNO3

OHHOHH

CH2OH

CO2HHHOHHO

OHHOHH

CO2H

CO2HHHOHHO

I II III

OHHOHH

CH2OH

CH2OHHHOHHO

OHHOHH

CO2H

CHOHHOHHO

IV

OHHOHH

CHO

CO2HHHOHHO

V

?

A) I B) II C) III D) IV E) V Ans: B

Topic: Reactions 34. Which aldohexose would yield an optically active aldaric acid when treated with nitric

acid?

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOOHH

CH2OH

CHOOHHHHO

IV

HHOHHO

CH2OH

CHOHHOHHO

V A) I B) II C) III D) IV E) V Ans: A

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Chapter 22

844

Topic: Reactions 35. Which compound or compounds would be formed when D-glucose is dissolved in

methanol and then treated with anhydrous acid?

OHO

HOOH

OH

OCH3 H3COOCH3

OCH3

OH3COOCH3

OHO

HOOCH3

OH

OH

I II

IVIII

OHO

HOOH

OH

OCH3

A) I B) II C) III D) IV E) I and IV Ans: E

Topic: Reactions

36. A D-aldohexose, Z, is subjected to a Ruff degradation. The degradation product is treated with nitric acid to yield an optically active aldaric acid. A possible structure for Z is:

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOOHH

CH2OH

CHOOHHHHO

IV A) I B) II C) III D) IV E) More than one of the above Ans: E

Page 845: 45669583 Organic Practice

Chapter 22

845

Topic: Reactions 37. Which of the following substances will afford an optically inactive product upon

reaction with nitric acid?

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOOHH

CH2OH

CHOOHHHHO

IV A) I B) II C) III and IV D) II, III and IV E) All of the above Ans: D

Topic: Reactions

38. Which of the following substances will afford a meso- product upon reaction with Br2/H2O ?

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOOHH

CH2OH

CHOOHHHHO

IV A) I B) II C) III and IV D) II, III and IV E) None of the above Ans: E

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846

Topic: Reactions 39. Which of these reacts with dilute HCl to produce methanol?

OOH

CH2OCH3

OHOH

III

O OH

OH

CH2OH

OHOCH3

I

O

OH

CH2OH

OH

II

IV

O

OH

H3COH2C CH2OH

OH

V

OH

OCH3

OH

OH

O

CH2OH

HOH2C OCH3

OH OH

A) I B) II C) III D) IV E) V Ans: D

Topic: Reactions 40. Which monosaccharide is recovered from the hydrolysis of glycogen?

A) D-Galactose B) D-Glucose C) D-Gulose D) Cellobiose E) Maltose Ans: B

Topic: Reactions

41. Which monosaccharide is recovered from the hydrolysis of starch? A) D-Galactose B) D-Glucose C) D-Gulose D) Cellobiose E) Maltose Ans: B

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Topic: Reagents 42. Sucrose reacts with which of these reagents?

A) C6H5NHNH2 B) Cu2+ C) Br2/H2O D) H3O+ E) Ag(NH3)2

+ Ans: D

Topic: Reagents

43. Which reagent would cause the following conversion to take place?

OHO

HOOH

OH

OCH3 H3COOCH3

OCH3

OH3COOCH3

?

A) Excess CH3OH and KOH B) Excess CH3OH and HCl C) Excess (CH3)2SO4 and OH- D) Excess CH3I and H3O+ E) Excess (CH3CO)2O Ans: C

Topic: Reagents

44. Select the reagent(s) needed to perform the following transformation.

OHO

HO

HO

HO

OHHO

HO

OHO

HO

OCH3

?

A) CH3I, KOH B)

O

O O

C) (CH3)2SO4, NaOH D) CH3OH, HCl E)

OCH3

O

Ans: D

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848

Topic: Reagents 45. Which reagent will distinguish between the members of the following pair?

OHHOHH

CH2OH

CH2OHOHHHHO

I II

OHHOHH

CH2OH

CHOOHHHHO

A) Ag(NH3)2

+ B) AgNO3/C2H5OH C) Br2/CCl4 D) HCl E) Hot KMnO4 Ans: A

Topic: Reagents

46. Which reagent will distinguish between the members of the following pair?

OHHOHH

CH2OH

CO2HOHHHHO

I II

OHHOHH

CH2OH

CHOOHHHHO

A) Ag(NH3)2

+ B) AgNO3/C2H5OH C) Br2/CCl4 D) HCl E) Hot KMnO4 Ans: A

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849

Topic: Reagents 47. Which reagent will distinguish between the members of the following pair?

OCH3HOCH3H

CH2OH

CHOOCH3HHHO

I II

OHHOHH

CH2OH

CHOOHHHHO

A) Ag(NH3)2

+ B) AgNO3/C2H5OH C) Br2/CCl4 D) KMnO4 E) HIO4 Ans: E

Topic: Reagents

48. Which of the following would give a positive test with Benedict's or Fehling's solution?

O

OCH3

HOH2C CH2OH

OH

HO

OHO

HO

OCH3

OH

OH

OHO

HOOCH3

OH

OH

OHO

HOOH

OCH3

OH

I II

IVIII A) I B) II C) III D) IV E) All of these Ans: C

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Chapter 22

850

Topic: Product Ratios 49. What is the ratio of products formed by the reaction of periodic acid with the following

compound?

OHHOHH

CH2OH

CHOOHHOHH

H2C=O

HCO2H

CO2

I 5 1 0 II 3 3 0 III 1 5 0 IV 1 4 1 V 0 4 2 A) I B) II C) III D) IV E) V Ans: C

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851

Topic: Product Ratios 50. What is the ratio of products formed by the reaction of periodic acid with the following

compound?

HHOOHH

CH2OH

CH2OHC O

OHH

H2C=O HCO2H CO2 I 5 1 0 II 3 3 0 III 1 5 0 IV 2 3 1 V 0 4 2 A) I B) II C) III D) IV E) V Ans: D

Topic: Product Ratios

51. Which of these is a component of the mixture formed when D-galactose is placed in aqueous base (de Bruyn - van Ekenstein transformation)?

HHOOHH

CH2OH

CHOOHHOHH

I II III

OHHOHH

CH2OH

CHOOHHHHO

OHHOHH

CH2OH

CHOHHOHHO

IV

HHOOHH

CH2OH

CH2OHC O

HHO

V

OHHHHO

CH2OH

CHOHHOOHH

A) I B) II C) III D) IV E) V Ans: E

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852

Topic: Named Reactions and Structure Identification 52. The Kiliani-Fisher Synthesis is the reaction of an aldose with:

A) Br2/H2O; then HCN; then H3O+; then Na-Hg, H2O B) HCN; then Ba(OH)2; then H3O+; then Na-Hg, H2O C) HCN; then H3O+; then Ba(OH)2; then Na-Hg, H2O D) Br2/H2O; then H2O2, Fe2(SO4)3 E) Br2/H2O Ans: B

Topic: Named Reactions and Structure Identification

53. The Ruff degradation is the reaction of an aldose with: A) Br2/H2O; then HCN; then H3O+; then Na-Hg, H2O B) HCN; then Ba(OH)2; then H3O+; then Na-Hg, H2O C) HCN; then H3O+; then Ba(OH)2; then Na-Hg, H2O D) Br2/H2O; then H2O2, Fe2(SO4)3 E) Br2/H2O Ans: D

Topic: Named Reactions and Structure Identification

54. An aldopentose, X, is subjected to a Kiliani-Fischer synthesis to produce two aldohexoses, Y and Z. Both Y and Z, when oxidized with nitric acid, yield optically active aldaric acids. Which structure represents X?

OHHOHH

CH2OH

CHOHHO

I II III

OHHOHH

CH2OH

CHOOHH

HHOHHO

CH2OH

CHOHHO

IV

OHHHHO

CH2OH

CHOOHH

V

HHOOHH

CH2OH

CHOHHO

A) I B) II C) III D) IV E) V Ans: B

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853

Topic: Named Reactions and Structure Identification 55. Compound X is a reducing sugar which, on hydrolysis, affords two molar equivalents of

D-glucose. This hydrolysis is catalyzed by an enzyme specific for glucosides of this type:

O

OH

OH

OR

CH2OH

OH What is the identity of X? A) Sucrose B) Lactose C) Maltose D) Cellobiose E) None of these Ans: C

Topic: Named Reactions and Structure Identification

56. A polysaccharide, Y, undergoes hydrolysis on catalysis by an enzyme which catalyzes the hydrolysis of cellobiose, but not maltose. Complete methylation and acid hydrolysis of the permethylated Y yields better than 95% of 2,4,6-tri-0-methyl-D-glucose. Which is a plausible structure for the repeating unit of Y?

O

OH

OR

OR

CH2OH

OH

O

OH

OR

OR

CH2OR

OH

O

OR

OR

OH

CH2OH

OH

O

OH

OR

OR

CH2OH

OH

O

OH

OH

OR

CH2OH

OR

I II III

IV VA) I B) II C) III D) IV E) V Ans: D

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854

Topic: Named Reactions and Structure Identification 57. If the methyl glycoside of an aldohexose is treated with HIO4, one molar equivalent of

HCHO is formed but no HCOOH. What size ring is present in the glycoside? A) Three-membered B) Four-membered C) Five-membered D) Six-membered E) Seven-membered Ans: C

Topic: Named Reactions and Structure Identification

58. The pyranose form of an aldohexose which can react 1:2 with acetone in the presence of acid is which of these?

OHO

OH

OH

OH

OH

OHO

OH

OH

OH

OH

OHO

HO

OHOH

OH

OHO

OHOH

OH

OH

I II

IV

III

V

OHO

HO

OHOH

OH

A) I B) II C) III D) IV E) V Ans: C

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855

Topic: Named Reactions and Structure Identification 59. Sugars that would yield the same phenylosazone are:

OHHOHH

CH2OH

CHOOHHHHO

I II III

OHHOHH

CH2OH

CHOHHOHHO

OHHHHO

CH2OH

CHOOHHHHO

IV

OHHOHH

CH2OH

CH2OHC O

HHO

V

HHOOHH

CH2OH

CHOOHHOHH

A) I and II B) II and III C) I, II, and III D) III and IV E) I, II, and V Ans: C

Topic: Named Reactions and Structure Identification

60. Which is not an intermediate monosaccharide in the Kiliani-Fischer synthesis of D-mannose from D-glyceraldehyde? A) D-Ribose B) D-Threose C) D-Arabinose D) D-Erythrose E) More than one of these Ans: E

Topic: Stereochemical Considerations

61. Reaction of D-ribose with bromine water would yield an optically: A) active aldonic acid. B) inactive aldonic acid. C) active aldaric acid. D) inactive aldaric acid. E) active uronic acid. Ans: A

Topic: Stereochemical Considerations

62. Reaction of D-ribose with HNO3 would yield an optically: A) active aldonic acid. B) inactive aldonic acid. C) active aldaric acid. D) inactive aldaric acid. E) inactive uronic acid. Ans: D

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856

Topic: Stereochemical Considerations 63. Which would undergo mutarotation in neutral aqueous solution?

II

O

OH

HO

OH

CH2OH

OH

O

OH

OCH3

OH

CH2OH

OH

IVIII

O

OH

OH

OH

CH2OH

OH

I

O

OH

OH

OH

CH2OH

OH

A) I B) II C) III D) IV E) More than one of these Ans: E

Topic: Stereochemical Considerations 64. Which of the following structures represent enantiomers?

OHHOHH

CH2OH

CHOHHOHHO

I II III

OHHOHH

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOOHHOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHHHO

A) I and II B) II and III C) III and IV D) III and V E) IV and V Ans: D

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Chapter 22

857

Topic: Stereochemical Considerations 65. Which of the following structures represent epimers?

OHHOHH

CH2OH

CHOHHOHHO

I II III

OHHOHH

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOOHHOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHHHO

A) I and II B) II and III C) III and IV D) III and V E) IV and V Ans: A

Topic: Stereochemical Considerations

66. Refer to the following structures. Which D-aldohexose would react with NaBH4 to yield an optically inactive alditol?

OHHOHH

CH2OH

CHOHHOHHO

I II III

OHHOHH

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOOHHOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHHHO

A) I B) II C) III D) IV E) V Ans: C

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Chapter 22

858

Topic: Stereochemical Considerations 67. Refer to the following structures. Which aldohexose when subjected to Fischer's end-

group interchange would be converted to a compound identical with itself?

OHHOHH

CH2OH

CHOHHOHHO

I II III

OHHOHH

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOOHHOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHHHO

A) I B) II C) III D) IV E) V Ans: B

Topic: Stereochemical Considerations

68. Which is an L-monosaccharide that would yield an optically active aldaric acid on oxidation by nitric acid?

OHHOHH

CH2OH

CHOOHHHHO

I II III

OHHHHO

CH2OH

CHOHHOOHH

HHOHHO

CH2OH

CHOOHHOHH

IV

OHHOHH

CH2OH

CH2OHC O

HHO

V

HHOHHO

CH2OH

CHOHHOHHO

A) I B) II C) III D) IV E) V Ans: D

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859

Topic: Stereochemical Considerations 69. Which is the only one of these classes of carbohydrates which can include optically

inactive members? A) Uronic acids B) Alditols C) Ketoses D) Glycosides E) Aldonic acids Ans: B

Topic: Stereochemical Considerations

70. What are the correct designations for the stereogenic centers in this aldose:

HHOHHO

CH2OH

CHOOHH

A) 2R,3S,4R B) 2R,3S,4S C) 2S,3R,4R D) 2S,3S,4R E) 2R,3R,4S Ans: B

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860

Topic: Combination Problems 71. Consider the structures of D-allose below:

D-Allose

OHHOHH

CH2OH

CHOOHHOHH

Which of the following structures represents L-allose?

OHHHHO

CH2OH

CHOHHOOHH

I II

OHHHHO

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOHHOOHH

III IV

HHOHHO

CH2OH

CHOHHOHHO

V

HHOHHO

CH2OH

CHOOHHOHH

A) I B) II C) III D) IV E) V Ans: B

Topic: Stereochemistry 72. Consider the structures below: what term(s) describe(s) the relationship between them?

OHHHHO

CH2OH

CHOHHOOHH

OHHHHO

CH2OH

CHOOHHOHH

A) Enantiomers B) Epimers C) Diastereomers D) Anomers E) More than one of the above Ans: E

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861

Topic: Combination Problems 73.

Consider the structures below. Which of the structures II-VI are epimers of I ?

OHHHHO

CH2OH

CHOHHOOHH

I II III

OHHHHO

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOHHOOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

VI

HHOHHO

CH2OH

CHOOHHOHH

A) II B) III C) IV D) V E) VI Ans: B

Topic: Combination Problems 74. Consider the structures below. An L-aldohexose, X, is treated with nitric acid to yield

an optically inactive aldaric acid. The same L-aldohexose, X, is subjected to a Ruff degradation and the degradation product is oxidized with nitric acid to produce an optically inactive aldaric acid. Which is a possible structure for X?

OHHHHO

CH2OH

CHOHHOOHH

I II

OHHHHO

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOHHOOHH

III IV

HHOHHO

CH2OH

CHOHHOHHO

V

HHOHHO

CH2OH

CHOOHHOHH

A) I B) II C) III D) IV E) V Ans: D

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862

Topic: Combination Problems 75. Consider the structures below. Which monosaccharides would yield an optically active

aldonic acid when oxidized with bromine water?

OHHHHO

CH2OH

CHOHHOOHH

I II III

OHHHHO

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOHHOOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

VI

HHOHHO

CH2OH

CHOOHHOHH

A) I, II, and III B) I, II, and V C) III, IV, and VI D) II, III, and IV E) All of these Ans: E

Topic: Combination Problems

76. Consider the structures above. Which monosaccharides would yield the same phenylosazone when treated with excess phenylhydrazine?

OHHHHO

CH2OH

CHOHHOOHH

I II III

OHHHHO

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOHHOOHH

IV V

HHOHHO

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

VI

HHOHHO

CH2OH

CHOOHHOHH

A) I and V B) I and III C) II and III D) III and VI E) IV and V Ans: C

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863

Topic: Combination Problems 77. Refer to the structures below. Which sugar(s) would yield an optically active aldaric

acid on oxidation with nitric acid?

OHHOHH

CH2OH

CHOHHO

I II III

HHOOHH

CH2OH

CHOOHH

OHHHHO

CH2OH

CHOHHO

IV V

HHOHHO

CH2OH

CHOHHO

OHHOHH

CH2OH

CHOOHH

A) I and III B) I, II, III, and V C) II D) III and IV E) I and V Ans: C

Topic: Combination Problems

78. Refer to the structures below. Which are L-sugars?

OHHOHH

CH2OH

CHOHHO

I II III

HHOOHH

CH2OH

CHOOHH

OHHHHO

CH2OH

CHOHHO

IV V

HHOHHO

CH2OH

CHOHHO

OHHOHH

CH2OH

CHOOHH

A) II and IV B) I, II, and III C) I and V D) III, IV, and V E) IV and V Ans: E

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Chapter 22

864

Topic: Combination Problems 79. Refer to the structures below. Which sugars would react with phenylhydrazine to yield

the same phenylosazone?

OHHOHH

CH2OH

CHOHHO

I II III

HHOOHH

CH2OH

CHOOHH

OHHHHO

CH2OH

CHOHHO

IV V

HHOHHO

CH2OH

CHOHHO

OHHOHH

CH2OH

CHOOHH

A) I and II B) III and IV C) I and V D) II and III E) III and V Ans: A

Topic: General Information

80. The D-glucose unit at the branching point of amylopectin has free hydroxyl groups at which positions? A) C2, C3, and C6 B) C2 and C3 C) C3 and C4 D) C3, C4, and C6 E) C4 and C6 Ans: B

Topic: General Information

81. Cellulose differs from chitin in which way? A) Cellulose has β-glycosidic linkages; chitin has ∝-glycosidic linkages. B) Cellulose contains only D-glucose units; chitin contains only N-acetyl-D-

glucosamine units. C) Cellulose cannot be hydrolyzed; chitin can be hydrolyzed. D) Cellulose has a linear structure; chitin has a helical structure. E) Cellulose chains are branched; chitin chains are unbranched. Ans: B

Topic: General Information

82. Cellulose lacks nutritive value for humans because: A) the products of its digestion are excreted without utilization. B) its conformation prevents attack by digestive enzymes. C) we lack the enzymes which can catalyze the hydrolysis of the glycosidic linkages. D) it passes through the digestive tract so rapidly. E) the molecules possess such a high molecular weight. Ans: C

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865

SHORT ANSWER QUESTIONS

Topic: General Information 83 Sugars that give positive tests with Benedict's or Tollens' solution are called

_______________. Ans: reducing sugars

Topic: General Information

84. Bromine water is a reagent that converts an aldose to an ___________. Ans: aldonic acid

Topic: General Information

85. The simplest carbohydrates (those that cannot be hydrolyzed to simpler carbohydrates) are called ______________. Ans: monosaccharides

Topic: General Information

86. Carbohydrates that hydrolyze to give a large number of molecules of monosaccharides are called _____________. Ans: polysaccharides

Topic: General Information

87. Carbohydrates are synthesized in green plants by _____________. Ans: photosynthesis

Topic: General Information

88. A monosaccharide containing six carbon atoms and an aldehyde functionality is called an _____________. Ans: aldohexose

Topic: General Information

89. Many carbohydrates exist in equilibrium with cyclic hemiacetals. Those carbohydrates that form a five-membered cyclic hemiacetal are called _____________. Ans: furanoses

Topic: General Information

90. Ordinary table sugar is a disaccharide called __________. Ans: sucrose

Topic: General Information

91. Milk contains a disaccharide called __________. Ans: lactose

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866

Topic: General Information 92. The method of lengthening the carbon chain of an aldose through the addition of HCN

followed by hydrolysis and reduction is called the ______________. Ans: Kiliani-Fischer synthesis

Topic: General Information

93. A polysaccharide found in the shells of lobsters, crabs, and in the exoskeletons of insects and spiders is called _________. Ans: chitin

Topic: Aldaric Acids 94. Draw the structure(s) of the γ-lactone(s) that can be formed from D-Glucaric acid.

CO2HOHHHHOOHHOHH

CO2H

D-glucaric acid Ans: CO2H

OHHHHOOHHOHH

CO2H

-H2O

CO2HOHHHOOHHOHH

CO

COHHHHOOHOHH

CO2H

O

D-glucaric acid γ−lactones

and

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867

Topic: Aldaric Acids 95. Consider the structure of D-erythrose, shown below. Draw the structure of the product

obtained upon treatment of D-erythrose with nitric acid. Give its IUPAC name and comment on its stereochemistry.

O

OHHOHH

CH2OH

H

D-erythrose Ans: The product, 2,3-dihydroxybutanedioic acid, is expected to be optically inactive,

due to a meso- configuration: (2R,3S) or (2S,3R). O

OHHOHH

CH2OH

H

HNO3

CO2HOHHOHH

CO2H

D-erythrose 2,3dihydroxybutanedioic acid (meso)

Topic: Periodate Oxidations 96. What products are expected from the reaction of 3-hydroxy-2,4-pentanedione with 2

molar equivalents of periodic acid? Ans: O O

OHOH H OH

O O+22 eq HIO4

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868

Topic: Periodate Oxidations 97. Suggest a simple chemical test that you might use to distinguish between 2,3-

pentanediol and 2,4-pentanediol? Ans: Periodic acid test: 2,3- pentanediol is expected to undergo oxidative cleavage with

periodic acid to afford acetic acid and propanoic acid. By contrast, no reaction is expected in an analogous treatment of 2,4-pentanediol, since the hydroxyl groups are separated by a methylene group.

OH OHOH

OH

HIO4 HIO4

OH

OOH

O

no reaction+

Topic: Kiliani Fischer Synthesis 98. What products are expected to be formed upon subjecting L-erythrose (shown below) to

the following reaction sequence? (Draw Fischer projection formulas) i) HCN; ii) Ba(OH)2; iii) H3O+; iv) Na(Hg), H2O, pH 3-5 Ans: Kiliani Fischer Synthesis:

O

HHOHHO

CH2OH

HO

HHOHHOHHO

CH2OH

H O

OHHHHOHHO

CH2OH

H

L-erythrose

+

i) HCN

ii) Ba(OH)2

iii) H3O+

iv) Na(Hg), H2O,

pH 3-5

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869

Topic: Ruff Degradation 99. What products are expected to be formed upon subjecting D-galactose (shown below) to

the following reaction sequence? (Draw Fischer projection formulas) i) Br2, H2O; ii) H2O2, Fe2(SO4)3

CHOOHHHHOHHOOHH

CH2OH

D-galactose Ans: Ruff degradation

CHOOHHHHOHHOOHH

CH2OH

CHOHHOHHOOHH

CH2OH

D-galactose

i. Br2, H2Oii. H2O2, Fe2(SO4)3

Topic: Epimers 100. Draw structures for 3 different epimers of D-glucose.

OHHOHH

CH2OH

CHOOHHHHO

D-Glucose Ans:

OHHOHH

CH2OH

CHOHHOHHO

OHHOHH

CH2OH

CHOOHHOHH

HHOOHH

CH2OH

CHOOHHHHO

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Chapter 23

870

MULTIPLE CHOICE QUESTIONS

Topic: General Lipid Types and Information 1. Which of the following statements regarding lipids is not true?

A) Lipids are soluble in non-polar organic solvents. B) All lipids have the same functional groups. C) Lipids include waxes, steroids, and triacylglycerols. D) Lipids have little in common except their solubility. E) Many lipids have biological roles. Ans: B

Topic: General Lipid Types and Information

2. Which of the following statements regarding triacylglycerols is not true? A) They undergo alkaline hydrolysis to yield soaps. B) They are liquid if they have alkene bonds. C) They are solid if they do not have alkene bonds. D) Some can be hydrogenated. E) They are soluble in water. Ans: E

Topic: General Lipid Types and Information

3. Which of the following statements regarding triacylglycerols is true? A) They form micelles when mixed with water. B) They are liquid if they are unsaturated. C) They are solid if they have alkyne bonds. D) They can be used to wash dirty dishes E) They are soluble in water. Ans: B

Topic: General Lipid Types and Information

4. Which of the following statements regarding triacylglycerols is not true? A) They are synthesized in the body by adipocytes. B) They have an odd number of carbon atoms. C) They are solid if they do not have alkene bonds. D) Those which can be hydrogenated, undergo a significant change in melting point

upon hydrogenation. E) They can be hydrolyzed to give glycerol and fatty acids. Ans: B

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871

Topic: General Lipid Types and Information 5. Which of the following statements regarding triacylglycerols is not true?

A) Some undergo autooxidation with oxygen from air. B) They are solid if they do not have alkene bonds. C) They form lipid bilayers. D) They form micelles in water. E) Two of the above are false statements. Ans: E

Topic: General Lipid Types and Information

6. Which of the following is a phosphatidic acid? CH2OOCR

CHOOCR'

CH2OOCR"

CH2OH

CHOOCR

CH2OOCR'

CH2OPO3H2

CHOH

CH2OH

CH2OOCR

CHOOCR'

CH2OPO3H2

CH2OPO3PO3H2

CHOOCR

CH2OOCR'

I II III

IV V A) I B) II C) III D) IV E) V Ans: D

Topic: General Lipid Types and Information 7. Which type of lipid gives these products on saponification:

HOCH2CHOHCH2OH RCO2¯ R'CO2¯ PO4

3¯ HOCH2CH2NH2 ? A) Fat B) Wax C) Lecithin D) Cephalin E) Plasmalogen Ans: D

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Topic: General Lipid Types and Information 8. Which type of lipid gives the following products on saponification?

HOCH2CHOHCH2OH RCO2¯ R'CO2¯ PO4

3¯ [HOCH2CH2N(CH3)3]+OH−

A) Fat B) Wax C) Lecithin D) Cephalin E) Plasmalogen Ans: C

Topic: General Lipid Types and Information 9. Which type of lipid gives these products on saponification:

HOCH2CHOHCH2OH RCO2¯ RCH2CHO PO4

3¯ HOCH2CH2NH2 ? A) Fat B) Wax C) Lecithin D) Cephalin E) Plasmalogen Ans: E

Topic: General Lipid Types and Information 10. Which of these lipids does not yield glycerol upon hydrolysis?

A) A lecithin B) A sphingolipid C) A cephalin D) A triacylglycerol E) A plasmalogen Ans: B

Topic: General Lipid Types and Information

11. Which of these lipids yields glycerol upon hydrolysis? A) A lecithin B) A phosphatidylserine C) A cephalin D) A triacylglycerol E) All of the above Ans: E

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Topic: General Lipid Types and Information 12. Which of these lipids yields choline upon hydrolysis?

A) A lecithin B) A sphingomyelin C) A cephalin D) A cerebroside E) Two of the above Ans: E

Topic: General Lipid Types and Information 13. Choline cannot be found as a product of hydrolysis of any representative of this class of

lipids. A) Sphingomyelins B) Lecithins C) Plasmalogens D) Waxes E) Both C) and D) Ans: D

Topic: General Lipid Types and Information

14. Choline cannot be found as a product of hydrolysis of any representative of this class of lipids. A) Cerebrosides B) Phosphatidylserine C) Plasmalogens D) Waxes E) None of the above yield choline upon hydrolysis Ans: E

Topic: General Lipid Types and Information 15. D-galactose is an example of a class of compounds that can be formed during the

hydrolysis of A) Sphingomyelins B) Cerebrosides C) Plasmalogens D) Waxes E) Both C) and D) Ans: B

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Topic: General Lipid Types and Information 16. Which of these is a wax?

A) CH3(CH2)20C=O

H

B) CH3(CH2)24COCH2(CH2)28CH3

O

C) CH3(CH2)7C=C(CH2)7COCH2CH3

H H O

D) CH2OOC(CH2)16CH3

CHOOC(CH2)14CH3

CH2OOC(CH2)14CH3

E) CH3(CH2)24CH2OH Ans: B

Topic: General Lipid Types and Information 17. Which of these is most likely to have properties resembling natural waxes?

O OI

O OII

O O

OIII

O

OIV

NH

O

OV

A) I B) II C) III D) IV E) V Ans: D

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Topic: General Lipid Types and Information 18.

OCH2CH2N(CH3)3 is a structural unit of which type of phosphatide? A) Cephalins B) Phosphatidyl serines C) Plasmalogens D) Lecithins E) Both C) and D) Ans: E

Topic: General Lipid Types and Information 19. OCH2CH2NH2 is a structural unit of which type of phosphatide?

A) Cephalins B) Phosphatidyl serines C) Plasmalogens D) Lecithins E) Both A) and C) Ans: E

Topic: Fats and Oils 20. Which of the following would serve as the basis for a simple chemical test that would

distinguish between stearic acid and oleic acid? A) NaOH/H2O B) NaHCO3/H2O C) HCl/H2O D) Ag(NH3)2

+ E) Br2/CCl4 Ans: E

Topic: Fats and Oils 21.

Which of the following would not be helpful in distinguishing between oleic acid, linoleic acid and linolenic acid? A) Examine the stoichiometry of the reaction with Br2, CCl4 B) Examine the stoichiometry of complete catalytic hydrogenation. C) Examine products obtained after subjecting the sample to catalytic hydrogenation D) Examine products obtained after subjecting the sample to : i) O3, CH2Cl2; ii) Zn,

CH3CO2H E) All of the above would be helpful. Ans: C

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Topic: Fats and Oils 22. Which of the following might be helpful in distinguishing between oleic acid and

linoleic acid? A) Examine the stoichiometry of the reaction with NaOH/H2O B) Examine the stoichiometry of complete catalytic hydrogenation. C) Examine products obtained after subjecting the sample to catalytic hydrogenation D) Examine products obtained after subjecting the sample to : i) O3, CH2Cl2; ii) Zn,

CH3CO2H E) Two of the above Ans: E

Topic: Fats and Oils 23. Which fatty acid is not likely to occur commonly in natural sources?

A) CH3(CH2)12COOH

B) CH3(CH2)14COOH

C)

H H

(CH2)7CO2HCH3(CH2)5

D)

H H H H

CH3(CH2)4 (CH2)7CO2HCH2

E) CH3(CH2)12CHCH2CO2H

CH3

Ans: E

24. Which fatty acid is not likely to occur commonly in natural sources? A) Tetradecanoic acid B) Pentadecanoic acid C) Hexadecanoic acid D) (9Z,12Z)-octadeca-9,12-dienoic acid E) (Z)-hexadeca-9-enoic acid Ans: B

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25. Which fatty acid is not likely to occur commonly in natural sources? A) (Z)- 11-Tetradecenoic acid B) (Z)- 9-Pentadecenoic acid C) Hexadecanoic acid D) (9Z,12Z)- 9,12-octadecadienoic acid E) (Z)-9-hexadecenoic acid Ans: B

26. Which fatty acid is likely to occur commonly in natural sources? OH

OI

OH

O

II

OH

OIII

OH

OIV

OH

OV

A) II B) I and IV C) II and III D) II, III and IV E) V Ans: E

Topic: Fats and Oils

27. Which of the following could be used to prepare myristic acid, CH3(CH2)12COOH? A) CH3(CH2)11CH2Br, CN-, heat; then H3O+, heat B) CH3(CH2)11CH2Br, Mg, (C2H5)2O; then CO2; then H3O+ C) CH3(CH2)12CHO, Ag2O, OH-; then H3O+ D) Answers A) and B) E) Answers A), B), and C) Ans: E

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Topic: Fats and Oils 28. Which of the following could be used to prepare myristic acid, CH3(CH2)12COOH?

A) CH3(CH2)11CH2Br, CN-, heat; then H3O+, heat B) CH3(CH2)11CH2Br, Mg, (C2H5)2O; then CO2; then H3O+ C) CH3(CH2)13CHO, Ag2O, OH-; then H3O+ D) Answers A) and B) E) Answers A), B), and C) Ans: D

Topic: Fats and Oils

29. Which of the following could be used to prepare stearic acid, CH3(CH2)16COOH? A) CH3(CH2)15CH2Br, CN-, heat; then H3O+, heat B) CH3(CH2)15CH2Br, Mg, (C2H5)2O; then HCHO; then H3O+ C) CH3(CH2)16CH2Br, NaOH; then KMnO4,OH-, H2O; then H3O+ D) Answers A) and B) E) Answers A) and C) Ans: E

Topic: Fats and Oils

30. How could you synthesize stearolic acid, CH3(CH2)7C≡C(CH2)7COOH from oleic acid, CH3(CH2)7CH=CH(CH2)7COOH? A) Br2, CCl4; then 3 NaNH2, heat; then H3O+ B) Li, liq. NH3; then H3O+ C) H2, Pd D) Peracid; then H3O+; then HA, H2O, heat E) excess HCl; then KOH, C2H5OH, heat Ans: A

Topic: Fats and Oils

31. Which of these reagents would not react with oleic acid? A) H2, Ni B) PBr3 C) CH3MgI D) NH3/H2O E) NaBH4 Ans: E

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Topic: Fats and Oils 32. Which of these reagents would not react with oleic acid?

A) H2, Ni B) DIBAL-H C) O3/CH2Cl2 D) NH3/H2O E) LAH Ans: B

Topic: Fats and Oils

33. Which of these reagents would not react with stearic acid? A) H2, Ni B) SOCl2 C) CH3MgI D) NH3/H2O E) LAH Ans: A

Topic: Fats and Oils

34. What would be the product, X, of the following reaction sequence?

CH3(CH2)12COOH Xi. SOCl2ii. NH3iii. Br2, NaOH

A) CH3(CH2)12CHCOOHBr

B) CH3(CH2)11CHCONH2

Br

C) CH3(CH2)11CH2NH2

D) CH3(CH2)12CONH2

E) CH3(CH2)12COBr

Ans: C

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Topic: Fats and Oils 35. The final product of the following reaction sequence would be:,

OH

O

OH

O

III IV

V

IIO

OH

O

O OH

I

OH

O

i. PBr3

ii. LiAlH[OC(CH3)3]iii. NaCN, HCliv. H3O+, heat

?

A) I B) II C) III D) IV E) V Ans: D

Topic: Fats and Oils 36. What would be the product of the following reaction sequence?

CH3(CH2)5CH=CH(CH2)7CO2H ?i. H2, Niii. SOCl2iii. CH3(CH2)14CH2OH, HA

A) CH3(CH2)5CH=CH(CH2)14CH3 B) CH3(CH2)5COOCH2(CH2)14CH3 CH3(CH2)5CH=CH(CH2)7COOCH2(CH2)14CH3C) CH3(CH2)14COOCH2(CH2)14CH3 D) CH3(CH2)13CHClCOOCH2(CH2)14CH3 E) CH3(CH2)5CH=CH(CH2)7COOCH2(CH2)14CH3 Ans: C

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Topic: Fats and Oils 37. The product of the following reaction sequence may be described as?

CH3(CH2)5CH=CH(CH2)7CO2H ?i. H2, Niii. SOCl2iii. CH3(CH2)14CH2OH, HA

A) Alkoxyalkane B) Alkyl alkanoate C) Alkyl alkenoate D) Acyl glycerol E) Acyl Alkane Ans: B

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Topic: Fats and Oils 38. The product of the following reaction sequence is nervonic acid. What is the structure

of nervonic acid?

H3O+

C24H44O2

C24H43O2K

HC CNa C10H18

C24H43N

C24H46O2

NaCN C23H43Cl

C10H17Na

ICH2(CH2)11CH2Cl

1-bromooctane NaNH2NH3(l)

KOHheat

H2, P-2 nervonic acid A)

H

HCH3(CH2)7

(CH2)13CO2H

B)

H H

CH3(CH2)7 (CH2)13CO2H

C)

H H

CH3(CH2)9 (CH2)11CO2H

D)

H

HCH3(CH2)13

(CH2)7CO2H

E)

H H

CH3(CH2)13 (CH2)7CO2H

Ans: B

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Topic: Fats and Oils 39. Which fatty acid is responsible for the putrid odor of rancid butter?

A) Valeric acid B) Myristic acid C) Stearic acid D) Oleic acid E) Butyric acid Ans: E

Topic: Fats and Oils

40. How could you convert an unsaturated fatty acid into a saturated fatty acid? A) KMnO4, OH-, heat B) OH-, H2O, heat; then H3O+ C) H2, Ni, pressure D) H3O+, H2O, heat E) O3; then Zn, HOAc Ans: C

Topic: Fats and Oils

41. Which is an untrue statement concerning the fatty acid moieties of naturally-occurring triacylglycerols? A) Generally, they possess an even number of carbon atoms. B) Most have unbranched carbon chains. C) The double bonds, when present, all are in the cis configuration. D) Where two or three double bonds are present in the same fatty acid moiety, they

comprise a conjugated system. E) The fatty acid moieties in a particular triacylglycerol usually are different. Ans: D

Topic: Fats and Oils

42. Which is not a correct statement concerning naturally-occurring triacylglycerols? A) The greater the degree of unsaturation, the higher the melting point. B) Saponification yields glycerol and a mixture of carboxylic acid salts. C) Solid examples are termed "fats." D) Regardless of the exact nature of the R groups, such compounds are water-

insoluble. E) Such compounds frequently, but less correctly, are called "triglycerides." Ans: A

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Topic: Fats and Oils 43. Of the saturated fatty acids found in fats and oils, this one normally is the most

abundant: A) Capric acid B) Lauric acid C) Myristic acid D) Palmitic acid E) Stearic acid Ans: D

Topic: Fats and Oils

44. The biosynthesis of one series of prostaglandins begins with which of these fatty acids? A) Palmitic acid B) Stearic acid C) Oleic acid D) Linoleic acid E) Arachidonic acid Ans: E

Topic: Fats and Oils

45. The ozonolysis of a fatty acid produces these fragments:

O OH

O

O O O What is the identity of the fatty acid? A) Stearic acid B) Palmitoleic acid C) Oleic acid D) Linoleic acid E) Linolenic acid Ans: D

Topic: Fats and Oils

46. How many isomers, including stereoisomers, exist for the triacylglycerol which, on saponification, gives 2 molar equivalents of palmitate and 1 molar equivalent of stearate? A) 1 B) 2 C) 3 D) 4 E) 6 Ans: C

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Topic: Soaps, Detergents, and Micelles 47. Consider a micelle composed of phosphatidyl choline, shown below. Which part(s) of

the molecule would form the hydrophilic surface of the micelle? CH2OOC15H31

CHOOC17H35

CH2OP

OOCH2CH2N(CH3)3

O

1

2

3

A) 3 B) 2 C) 1 D) 1 and 2 E) 2 and 3 Ans: A

Topic: Soaps, Detergents, and Micelles

48. Which of these is a detergent? A) CH3(CH2)16COO-Na+ B) [CH3(CH2)14COO-]2Ca+2 C) CH3(CH2)10CH2SO3

-Na+ D) HOCH2CHOHCH2OH E) CH3(CH2)14CH2SH Ans: C

Topic: Terpenes

49. Which compound is a sesquiterpene?

III IV V

I II

OH

A) I B) II C) III D) IV E) V Ans: D

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Topic: Terpenes 50. Which structure represents a terpene likely to be found in nature?

III IV

I II

OOH

V A) I B) II C) III D) IV E) V Ans: C

Topic: Terpenes

51. To which class of terpenes does the terpene shown below, bisabolene, belong?

A) Monoterpenes B) Sesquiterpenes C) Diterpenes D) Triterpenes E) Tetraterpenes Ans: B

Topic: Terpenes

52. How many isoprene units are in vitamin A?

OH

A) 1 B) 2 C) 3 D) 4 E) More than 4 Ans: D

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Topic: Terpenes 53. In β-carotene, how many tail-to-tail links of isoprene units are there?

A) 1 B) 2 C) 3 D) 4 E) More than 4 Ans: A

Topic: Terpenes

54. Which compound below does not obey the isoprene rule?

IIIOH

IV V

OH

HO

I IIOH

A) I B) II C) III D) IV E) V Ans: D

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Topic: Terpenes 55. Which of the following compounds would be most likely to be found in nature? (Hint:

recall the isoprene rule.)

III IV

V

OH

OH OH

OH

I II

OH

A) I B) II C) III D) IV E) V Ans: D

Topic: Rubber

56. Which is the proper representation of three successive isoprene units in natural rubber?

III IV

V

I II

H H

H

H

H

H

H H H H

H

H

H

H

H

A) I B) II C) III D) IV E) V Ans: B

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Topic: Rubber 57. In the vulcanization of rubber,

A) natural rubber is heated with sulfur. B) reaction occurs at allylic positions. C) cross-linking results in a hardening of the rubber. D) disulfide bridges are formed. E) All of the above Ans: E

Topic: Rubber

58. Which is the repeating unit of natural rubber?

I II III IV V A) I B) II C) III D) IV E) V Ans: A

Topic: Steroids

59. What product would be obtained by catalytic hydrogenation of 5-cholesten-3β-ol? A) 5β-Cholestan-3β-ol B) 5∝-Cholestan-3β-ol C) 5∝-Cholestan-3∝-ol D) 5β-Cholestan-3∝-ol E) 5-Cholesten-3β,6∝-diol Ans: B

Topic: Steroids

60. Which reagent might be used to convert 5∝-cholest-1-en-3-ol into 5∝-cholestan-3-ol? A) CrO3/pyridine B) KMnO4/H2O C) CH3MgI D) H2/Pt E) Li/C2H5NH2 Ans: D

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Topic: Steroids 61. Which reagent might serve as the basis for a simple chemical test that would distinguish

between 5∝-cholest-1-en-3-one and 5∝-cholestan-3-one? A) Ag(NH3)2

+ B) CrO3/H2SO4 C) Br2/CCl4 D) NaOH/H2O E) C6H5NHNH2 Ans: C

Topic: Steroids

62. The synthesis of cortisone required placing a ketone function at the 11-position of a steroid. Where is position 11?

I

II

IIIIV

V

A) I B) II C) III D) IV E) V Ans: C

Topic: Steroids

63. How many stereogenic centers are there in cholesterol?

HO A) 2 B) 4 C) 6 D) 8 E) 16 Ans: D

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Topic: Steroids 64. Which is an untrue statement concerning cholesterol?

A) Cholesterol decolorizes a solution of Br2 in CCl4. B) Cholesterol reacts with 2,4-dinitrophenylhydrazine. C) Cholesterol is optically active. D) Cholesterol is water-insoluble. E) All of the above are true. Ans: B

Topic: Steroids

65. The reaction of cholesterol with dilute aqueous KMnO4 at 0–5°C produces which of these compounds (A and B rings only shown)?

HOOH

HOOH

HO HOOHHO

HOOHHO

HO OO

I II III

IV VA) I B) II C) III D) IV E) V Ans: D

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Topic: Steroids 66. In the biosynthesis of vitamin D2, which alkane bond of ergosterol is cleaved?

II I

IV

HO IIIV

A) I B) II C) III D) IV E) V Ans: D

Topic: Steroids

67. Which of the following is a female sex hormone? A) Ergosterol B) Estradiol C) Cortisone D) Androsterone E) Cholic acid Ans: B

Topic: Steroids

68. Which of these is a correct systematic name for progesterone?

O

O

Progesterone A) 2-Estrene-4,20-dione B) 5-Androstene-4,19-dione C) 4-Pregnene-3,20-dione D) 5-Cholestene-5,19-dione E) 4-Cholene-3,20-dione Ans: C

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Topic: Steroids 69. Shown below is the formula for the antiinflammatory drug called prednisone. What is a

correct systematic name for prednisone?

O

O

O OH

Prednisone

OH

A) 17∝,21-Dihydroxypregna-1,4-diene-3,11,20-trione B) 17β,21-Dihydroxypregna-1,4-diene-3,11,20-trione C) 17∝,19-Dihydroxypregna-1,4-diene-3,11,20-trione D) 17β,19-Dihydroxypregna-1,4-diene-3,11,20-trione E) None of the above Ans: A

Topic: Steroids

70. What product would you expect when progesterone is treated with one molar equivalent of hydrogen in the presence of a platinum catalyst?

O

O

Progesterone A) 5∝-Pregnane-3,20-dione B) 5β-Pregnane-3,20-dione C) 5∝-Estrane-3,20-dione D) 5β-Estrane-3,20-dione E) 5∝-Androstane-3,20-dione Ans: A

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Topic: Steroids 71. Which is the correct systematic name for the steroid shown below?

HO

H3C

CH3

H

H

HH

A) 5∝-Androstan-3∝-ol B) 5β-Androstan-3β-ol C) 5β-Androstan-3∝-ol D) 5∝-Androstan-3β-ol E) 5β-Estan-3β-ol Ans: D

Topic: Steroids

72. Which of these is a male sex hormone? A) Estrone B) Testosterone C) Cholic acid D) Cortisone E) Estradiol Ans: B

Topic: Prostaglandins

73. Which of the following characteristics are found in the class of C20 carboxylic acids called prostaglandins? A) a five membered ring B) One or more double bonds C) Several oxygen containing groups D) Two of the above E) All of the above Ans: E

SHORT ANSWER QUESTIONS

Topic: Lipids 74. Unlike carbohydrates and proteins, which are defined in terms of their structures, lipids

are defined in terms of _____________. Ans: the physical operation used to isolate them

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Topic: Fats and Oils 75. Saturated fatty acids pack efficiently. Therefore the corresponding triacylglycerols tend

to be __________ at room temperature and are called __________. Ans: solid; fats

Topic: Fats and Oils

76. Unsaturated fatty acids have a bend in the carbon chain that interferes with packing. Therefore the corresponding triacylglycerols are generally __________ at room temperature and are called _______. Ans: liquid; oils

Topic: Fats and Oils

77. The primary function of triacylglycerols (triglycerides) in animals is _____________. Ans: energy storage

Topic: Fats and Oils

78. Salts of long-chain fatty acids are known as ___________. Ans: soaps

Topic: Terpenes

79. Terpenes are built up from two or more five-carbon units known as __________. Ans: isoprene units

Topic: Terpenes

80. When natural rubber is heated with sulfur, a reaction takes place that produces _____________ between the polymer chains. This process is known as _____________.Ans: cross-links; vulcanization

Topic: Steroid Hormones

81. There are three major classes of sex hormones: a. female sex hormones [or ____________] b. male sex hormones [or ____________] c. pregnancy hormones [or ______________] Ans: a. estrogens; b. androgens; c. progestins

Topic: Fats and Oils

82. Sphingolipids, proteins, and polysaccharides make up ___________, the protective coating around nerve fibers. Ans: myelin

Topic: Fats and Oils

83. Explain how soap removes dirt from clothes. Ans: The hydrophobic end dissolves in the dirt and oil, forming a micelle with an ionic

outer layer. The outer layer is hydrophilic and makes it easy for the micelle to wash away, carrying the dirt with it.

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Topic: Fats and Oils 84. Myelin, the protective coating around nerve fibers, is made up of ___________.

Ans: sphingolipids, proteins, and polysaccharides

Topic: Fats and Oils 85. The characteristic odor of rancid butter is attributed to ___________.

Ans: the release of butyric acid during decomposition.

Topic: Fats and Oils 86. In naturally occurring polyunsaturated fatty acids, the relative position of double bonds

is rarely ___________. Ans: conjugated

Topic: Fats and Oils 87. There is growing evidence that “trans” fats are associated with an increased risk of

___________, and the FDA now requires “trans fat” information to be provided on nutrition labels. Ans: cardiovascular disease

Topic: Fats and Oils 88. In naturally occurring polyunsaturated fatty acids, the stereochemistry of the double

bonds is rarely ___________. Ans: trans-

Topic: Fats and Oils 89. Prolonged heating of naturally occurring polyunsaturated fats may cause the

stereochemistry of the double bonds to change from ___________. Ans: cis- to trans-

Topic: Fats and Oils 90. Most waxes, commonly found as protective coatings on skin, fur, hair, leaves, fruits,

etc., are ____________. Ans: Esters of long chain fatty acids and long chain alcohols.

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Topic: Fats and Oils 91. Olestra, a synthetic fat substitute, contributes nothing to the caloric value of foods

prepared with it, because it passes through the body without being digested. Why are the lipases, responsible for facilitating normal fat hydrolysis, unable to facilitate the hydrolysis of olestra? Ans: In order for a lipase to catalyze hydrolysis, the fat molecule must be accepted into

the active site of the enzyme. Although olestra contains 6-8 ester groups, the molecule is extremely bulky: this steric bulk prevents lipases from accepting the molecule into their active sites. Consequently, the olestra is not hydrolyzed, hence not absorbed, so that it adds nothing to the caloric value of foods prepared with it.

Topic: Fats and Oils 92. How could you synthesize stearolic acid, CH3(CH2)7C≡C(CH2)7COOH from oleic acid,

CH3(CH2)7CH=CH(CH2)7COOH? Specify stoichiometric details, providing a brief explanation of your rationale. Ans:

Topic: Fats and Oils 93. How are soaps and phosphatides similar in their interaction with water?

Ans: Both have polar and non-polar groups, so that they appear to “dissolve” when mixed with water. In actuality, they tend to form spherical micelles: the molecules aggregate in such a way that the polar groups of all the molecules in the micelle face the water, while the non-polar groups face inward, toward the center of the micelle, thus maximizing both hydrophilic as well as hydrophobic interactions.

Topic: Fats and Oils 94. Suggest a reasonable synthetic strategy for the synthesis of N,N-dimethylstearamide ,

CH3(CH2)16CON(CH3)2 from oleic acid, cis 9-octadecenoic acid Ans: i) H2,Ni; ii) PBr3; iii) (CH3)2NH

PBr3

CH3(CH2)16CO2H

CH3(CH2)16COBr

H2Ni

(CH3)2NH

CH3(CH2)7CH=CH(CH2)7CO2H

CH3(CH2)16CON(CH3)2

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898

Topic: Synthesis 95. One of the intermediates in a prostaglandin synthesis is shown below.

OO CHO

NO2CN

Which reaction might be employed to make this molecule from 1,1-dimethoxy-3-nitropropane and an appropriate α,β-unsaturated aldehyde? Show the structural details of the reagents as well as any catalysts that might be needed. Ans: Deprotonation (with base) of the active hydrogen alpha to the –NO2 group would

afford a nucleophilic species. Conjugate addition (Michael reaction) of this species to either isomer (cis/trans) of the α,β-unsaturated aldehyde drawn below should afford the desired compound in acceptable yields.

CN

O

CNO

orOO CHO

NO2CN

OO

NO2

+ base

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899

Topic: Soaps and Synthetic Detergents 96. Draw the structures of the following substances, in which the alkyl portion is

CH3(CH2)12−: sodium carboxylate, sodium alkanesulfonate and sodium alkyl sulfate Explain why these substances may be useful as “dirt removers”. Ans:

O−Na+

O

S O−Na+

O

O

OS

O

O

O−Na+

sodium carboxylate

sodium alkanesulfonate

sodium alkyl sulfate

Each of these substances has a polar “head” and a non-polar “tail”. This allows them to form micelles when mixed with water. These micelle clusters are dispersed throughout the aqueous phase, with the polar heads on the outside and the non-polar ends on the inside of the spherical clusters. When these micelles come into contact with the non-polar, oily surface of “dirt”, the dirt gets attracted to the non-polar center of the micelle, where it is then “trapped”. Upon rinsing, the micelles, along with the trapped dirt, get washed away.

Topic: Terpenes 97. What products would be obtained from the ozonolysis of zingiberine, found in the oil of

ginger?

Zingiberine

i) O3ii) Zn, CH3CO2H

?

Ans:

O

O

O

O OO+ +

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900

Topic: Terpenes 98. Identify the bonds that link the isoprene units in α-farnesene, shown below. How are

these units linked: head to head, tail to head or tail to tail ?

α-farnesene Ans:

α-farnesene

head

tail

tail

tail

head

head

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901

Topic: Analysis and Structure Elucidation 99. A compound “Z” (C10H16), has λmax at 184 nm in its UV spectrum. Catalytic

hydrogenation of Z affords a mixture of diasteromers, which upon separation are identified to be cis-1-isopropyl-4-methylcyclohexane and trans-1-isopropyl-4-methylcyclohexane. Upon ozonolysis, Z yields formaldehyde and 3-acetyl-6-oxoheptanal. Suggest a structure for Z that is consistent with all of the above data, clearly explaining your rationale. Ans:

excess H2, Ni*

cis- and trans-

λmax=184 nmozonolysis

H2C=O +

O

*O

O

- IHD for Z: (C10H22 - C10H16)/2 = 3 - Hydrogenation affords 1-isopropyl-4-methylcyclohexane: so, Z must have the same carbon skeleton, along with 2 pi bonds, i.e., 1 ring and 2 pi bonds (so that IHD =3) - Examination of the above carbon skeleton suggests that the pi bonds cannot constitute an alkyne, so that the pi bonds must be present as 2 double bonds. - λmax at 184 nm in its UV spectrum suggests that these pi bonds are not conjugated. - The stereochemistry of the hydrogenation products suggests that there must be a pi bond at C-4 and a chiral center at C-1: hydrogenation eliminates the asymmetry (and therefore chirality) at C-4. Hydrogenation from both faces of the pi bond at C-4 would lead to cis- and trans- orientation of the methyl and isopropyl groups on the cyclohexane ring. - The ozonolysis products suggest the position of the 2 double bonds: since there are only 2 products, one bond must be within the ring, the other outside the ring.

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MULTIPLE CHOICE QUESTIONS

Topic: Isoelectric Points and pH 1. Which amino acid would have its isoelectric point near pH 10?

I II III

CH2COO

NH3 NH2

H3NCH2CH2CH2CH2CHCOO

NH3

H3NCHCOO

IV VNH3

CH2CHCOOHO

NH3

HOOCCH2CH2CHCOO

A) I B) II C) III D) IV E) V Ans: B

Topic: Isoelectric Points and pH

2. Which amino acid would have its isoelectric point near pH 3?

NH3

H3CCHCOO

NH2

H2NCCH2CH2CH2CHCOO

NH2

I II III

NH2

H3NCH2CH2CH2CH2CHCOO

IV V

NH3

CH2CHCOO

NH3

HOOCCH2CH2CHCOO

A) I B) II C) III D) IV E) V Ans: C

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903

Topic: Isoelectric Points and pH 3. Which amino acid would have its isoelectric point near pH 10?

CH2CH2CH2NH3

H2N HCO2

I II III

IV V

CH2CH2CO2H

H3N HCO2

CH2SH

H NH3

CO2

CH2C6H5

H3N HCO2

CH2OH

H3N HCO2

A) I B) II C) III D) IV E) V Ans: A

Topic: Isoelectric Points and pH 4. Which amino acid would have its isoelectric point near pH 10?

A) Glycine B) Tryptophan C) Serine D) Proline E) Lysine Ans: E

Topic: Isoelectric Points and pH 5. Which amino acid would not have its isoelectric point in the pH range 5-7?

A) Leucine B) Threonine C) Methionine D) Arginine E) Cystine Ans: D

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904

Topic: Isoelectric Points and pH 6. Which amino acid would not have its isoelectric point in the pH range 5-7?

A) Glycine B) Proline C) Cysteine D) Glutamine E) All of these amino acids have isoelectric point in the pH range 5-7 Ans: E

Topic: Isoelectric Points and pH 7. What might be concluded upon determining that an unknown amino acid has its

isoelectric point near pH 10? A) It must have a hydrophobic side chain B) It must have a hydrophilic side chain C) Its side chain must contain a basic group D) Its side chain must contain an acidic group E) None of the above is a valid conclusion Ans: C

Topic: Isoelectric Points and pH 8. What might be concluded upon determining that an unknown amino acid has its

isoelectric point near pH 3? A) It must have a hydrophobic side chain B) It must have a hydrophilic side chain C) Its side chain must contain a basic group D) Its side chain must contain an acidic group E) None of the above is a valid conclusion Ans: D

Topic: Isoelectric Points and pH 9. The pH at which the concentration of the dipolar ion (zwitterion) form of an amino acid

is at a maximum and the cationic and anionic forms are at equal concentrations is termed the A) end point. B) equivalence point. C) neutral point. D) isoelectric point. E) dipolar point. Ans: D

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905

Topic: Isoelectric Points and pH 10. What is the pI of the following amino acid?

HO2C (CH2)n CO2H

NH2

pKa1= 2.4 pKa2= 10.0 pKa3= 4.0

α-CO2H α-NH3+ R group

A) 1.6 B) 3.2 C) 5.5 D) 6.2 E) 7.0 Ans: B

Topic: Isoelectric Points and pH 11 What is the pI of the following amino acid?

HO2C (CH2)n CO2H

NH2

pKa1= 2.2 pKa2= 9.7 pKa3= 4.3

α-CO2H α-NH3+ R group

A) 2.1 B) 3.2 C) 5.9 D) 6.5 E) 7.0 Ans: B

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906

Topic: Isoelectric Points and pH 12. What is the pI of the following amino acid?

HO2C (CH2)n NH2

NH2

pKa1= 2.2 pKa2= 9.0 pKa3= 10.5

α-CO2H α-NH3+ R group

A) 1.5 B) 6.3 C) 5.6 D) 9.8 E) 6.8 Ans: D

Topic: Isoelectric Points and pH 13. What is the pI of the following amino acid?

HO2C (CH2)n CH3

NH2

pKa1= 2.4 pKa2= 9.6

α-CO2H α-NH3+

A) 12 B) 3.6 C) 4.8 D) 6.0 E) 7.2 Ans: D

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907

Topic: Isoelectric Points and pH 14. Consider the following tripeptide:

H2N-leu-lys-phe-CO2H

NH2 What is the best estimate of the pI of this compound?

COOH NH3+ R

pKa pKa pKa pI

leu 2.4 9.6 6.0 lys 2.2 9.0 10.5 9.8 phe 1.8 9.1 5.5

A) 6.2 B) 7.1 C) 9.2 D) 10.1 E) 11.3 Ans: D

Topic: Isoelectric Points and pH 15. What would be the predominant form of lysine in water at pH 14?

CO2H

NH3

H3N CO2

NH3

H3N CO2

NH2

H3N

CO2

NH3

H2N CO2

NH2

H2N

I II III

IV V A) I B) II C) III D) IV E) V Ans: E

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908

Topic: Isoelectric Points and pH 16. The predominant form of aspartic acid in water at pH 1 would be:

HO2CCO2H

NH3

O2CCO2H

NH3

HO2CCO2

NH3

O2CCO2H

NH2

O2CCO2

NH2

I II III

IV V A) I B) II C) III D) IV E) V Ans: A

Topic: Isoelectric Points and pH 17. For the accompanying fully-protonated amino acid, what is the arrangement of pKa

values in order of increasing magnitude? HO2C

CO2H

NH3III

III

A) I < II < III B) II < I < III C) III < I < II D) III < II < I E) II < III < I Ans: C

Topic: Amino Acid Structure 18. Which of these amino acids contains a hydrophobic side chain?

A) Lysine B) Serine C) Methionine D) Arginine E) Cysteine Ans: C

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Topic: Amino Acid Structure 19. Which of these natural amino acids contains an amide function?

A) Asparagine B) Proline C) Arginine D) Histidine E) None of these Ans: A

Topic: Amino Acid Structure

20. Which of these natural amino acids contains a heterocyclic ring? A) Asparagine B) Proline C) Arginine D) Histidine E) Two of these Ans: E

Topic: Amino Acid Structure 21. Which of these natural amino acids contains an amide function?

A) Asparagine B) Methionine C) Cysteine D) Glutamine E) Two of these Ans: E

Topic: Amino Acid Structure 22. Which of these natural amino acids contains two carboxylic acid groups?

A) Cystine B) Cysteine C) Glutamic acid D) A and B E) A and C Ans: A

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Topic: Amino Acid Structure 23. Which of these natural amino acids contains a phenolic group?

A) Phenylalanine B) Tyrosine C) Tryptophan D) 4-Hydroxyproline E) Serine Ans: B

Topic: Amino Acid Structure 24. Which of these natural amino acids contains a pyrrolidine ring?

A) Phenylalanine B) Tyrosine C) Tryptophan D) 4-Hydroxyproline E) Serine Ans: D

Topic: Amino Acid Structure 25. Which of these natural amino acids contains an indole ring?

A) Phenylalanine B) Tyrosine C) Tryptophan D) 4-Hydroxyproline E) Asparigine Ans: C

Topic: Amino Acid Structure 26. Which of these natural amino acids contains an imidazole ring?

A) Histidine B) Lysine C) Tryptophan D) 4-Hydroxyproline E) Two of the above Ans: A

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Topic: Amino Acid Structure 27. Which of these natural amino acids contains an –OH group?

A) Serine B) Threonine C) Tyrosine D) Two of these E) All of these Ans: E

Topic: Amino Acid Structure 28. Which of these natural amino acids, when present in a polypeptide, is likely to exhibit

significant hydrogen bonding through its side chain? A) Serine B) Threonine C) Tyrosine D) Two of these E) All of these Ans: E

Topic: Amino Acid Structure 29. Which of these natural amino acids, when present in a polypeptide, is not likely to

exhibit significant hydrogen bonding through its side chain? A) Leucine B) Threonine C) Tyrosine D) Serine E) All of these are likely to exhibit significant hydrogen bonding through the side

chain Ans: A

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Topic: Amino Acid Structure 30.

Which amino acid is least likely to be found in a natural protein?

NH2

H HCO2H

I II III

IV V

CH3

H3N HCO2

CH2OH

H3N HCO2

CH2C6H5

H3N HCO2

CH3

H NH3

CO2

A) I B) II C) III D) IV E) V Ans: D

Topic: Amino Acid Structure

31. Which amino acid is unlikely to be found in a natural protein?

CH3

H3N HCO2

I II III

IV V

CH2OH

H3N HCO2

CH2C6H5

H3N HCO2

H

H3N HCO2

CH2SH

H NH3

CO2

A) I B) II C) III D) IV E) V Ans: D

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913

Topic: Amino Acid Structure 32. Which of these amino acids is formed from a precursor amino acid only after the latter

has been incorporated into a polypeptide chain? A) Serine B) Arginine C) Isoleucine D) Tryptophan E) Hydroxyproline Ans: E

Topic: Amino Acid Structure 33. Which of these amino acids is described as an “essential” amino acid?

A) Methionine B) Phenylalanine C) Isoleucine D) Tryptophan E) All of these are “essential” amino acids Ans: E

Topic: Amino Acid Structure 34. Which of these amino acids is described as an “essential” amino acid?

A) Threonine B) Glycine C) Tyrosine D) Serine E) All of these are “essential” amino acids Ans: A

Topic: Amino Acid Structure 35. Pipecolic acid logically would be substituted for which natural amino acid in the

synthesis of peptide analogs?

NH

CO2H

Pipecolic acid

A) Histidine B) Proline C) Tryptophan D) Phenylalanine E) Tyrosine Ans: B

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914

Topic: Amino Acid Structure

36. Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?

CO2H

NH2

HO

A) Tyrosine B) Proline C) Tryptophan D) Phenylalanine E) Tyrosine Ans: A

Topic: Amino Acid Structure 37.

Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?

CO2H

NH2HS A) Methionine B) Cysteine C) Cystine D) Tyrosine E) It could be substituted for all of these amino acids Ans: D

Topic: Amino Acid Structure 38.

Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?

CO2H

NH2

HO2C

A) Aspartic acid B) Glutamine C) Lysine D) Asparagine E) Glutamic acid Ans: E

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915

Topic: Amino Acid Structure 39.

Logically, the following “unnatural” amino acid would be substituted for which natural amino acid in the synthesis of peptide analogs?

CO2H

NH2

H2N

A) Leucine B) Lysine C) Arginine D) Alanine E) Valine Ans: B

Topic: Synthesis and Reactions of Amino Acids 40. What product would be obtained upon treating alanine with the following reagent ?

O Cl

O

O

O

NH3

CO2 O NH

O

CO2HNH3

NH

CO2H O

O

NH2

I II III

IV V A) I B) II C) III D) IV E) V Ans: C

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916

Topic: Synthesis and Reactions of Amino Acids 41. Which of the following would provide a synthesis of alanine?

A) CH2=CHCH2OH, HBr, CrO3/H2SO4/H2O; then xs NH3 B) Potassium phthalimide, ClCH2CO2C2H5; then KOH/H2O; then HCl C) Potassium phthalimide, C6H5CH2Br; then KOH/H2O; then CO2,H3O+ D) CH3CH2COOH, (C6H5)3CNa; then NH3 E) Answers A) and B) Ans: A

Topic: Synthesis and Reactions of Amino Acids 42. Which of the following would provide a synthesis of valine?

A) (CH3)2C=CHCH2OH, HBr/peroxides; CrO3/H2SO4/H2O; then xs NH3 B) Potassium phthalimide, (CH3)2CHCHClCO2C2H5; then KOH/H2O; then HCl C) Potassium phthalimide, (CH3)2CHCH2Br; then KOH/H2O; then CO2,H3O+ D) CH3CH2COOH, (C6H5)3CNa; then NH3 E) Answers A) and B) Ans: A

Topic: Synthesis and Reactions of Amino Acids 43. Which of the following would provide a synthesis of leucine?

A) (CH3)2C=CHCH2OH, HBr/peroxides, CrO3/H2SO4/H2O; then excess NH3 B) Potassium phthalimide, BrCH(CO2C2H5)2; (CH3)2CHCHClCO2C2H5; then

KOH/H2O; then HCl (85%), heat C) Potassium phthalimide, BrCH(CO2C2H5)2; (CH3)2CHCH2Br; then KOH/H2O;

then HCl (85%), heat D) (CH3)2CHCOOH, PCl5; then NH3 E) Answers A) and C) Ans: C

Topic: Synthesis and Reactions of Amino Acids 44. Which of the following would provide a synthesis of phenylalanine?

A) Phenylacetaldehyde, NH3, HCN; H3O+, heat B) Potassium phthalimide, BrCH(CO2C2H5)2; C6H5CH2Br; then KOH/H2O; then HCl

(85%), heat C) Potassium phthalimide, (C6H5)CH2CH2Br; then KOH/H2O; then HCl (85%), heat D) C6H5CH2COOH, SOCl2; then NH3 E) Answers A) and B) Ans: E

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917

Topic: Synthesis and Reactions of Amino Acids 45. What product(s) would you expect from the following reaction?

Tyrosine + Br2 (excess) ?H2O

CO2

Br

BrHO NH3

CO2

NH3HO

Br

Br

I II III

IV V

CO2

Br NH3

HO NH3

Br

OCO2

NH3HO

Br

A) I B) II C) III D) IV E) V Ans: B

Topic: Synthesis and Reactions of Amino Acids

46. Why is this sequence, CH2=CHCH2OH + HBr, then CrO3/H2SO4/H2O, finally xs NH3, not a good method for the preparation of L-alanine? A) NH3 is not sufficiently nucleophilic to perform the final step. B) HBr does not add to substituted alkenes. C) 1° alcohols are not oxidized by CrO3 in acidic solution. D) Initial HBr addition produces a racemic intermediate which leads to racemic

product. E) Steric hindrance precludes nucleophilic substitution at a 2° carbon atom. Ans: D

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918

Topic: Synthesis and Reactions of Amino Acids 47. What products would you expect from the following reaction?

O NH

OH2Pd

?

A) NH

OH O+

B) H2NCO2 ++

C) H2N+O O

D) O NH

E) OH H2NCO2 ++

Ans: B

Topic: Synthesis and Reactions of Amino Acids 48. Which is an isolable intermediate in the Strecker synthesis of an amino acid?

I II III

IV V

R CO2H

X

R CN

NH2

R OH

NH2

R CHO

NH2CO2

NH

O

CO2

CO2

R

A) I B) II C) III D) IV E) V Ans: B

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919

Topic: Protein Structure 49. The primary structure of a protein refers to its:

A) sequence of amino acid residues. B) disulfide bonds. C) helical structure. D) hydrogen bonding. E) All of these Ans: A

Topic: Protein Structure

50. The secondary structure of proteins is derived from: A) peptide linkages. B) disulfide linkages. C) hydrogen bond formation. D) hydrophobic interactions. E) acid-base interactions. Ans: C

Topic: Protein Structure

51. Which attractive force is responsible for maintaining the tertiary structure of a protein? A) Disulfide linkages B) Hydrogen bonds C) van der Waals forces D) Hydrophobic interactions E) All of these Ans: E

Topic: Protein Structure

52. The occurrence of this amino acid in a polypeptide chain disrupts an ∝-helix: A) Proline B) Alanine C) Methionine D) Histidine E) Tyrosine Ans: A

Topic: Protein Structure

53. Disulfide bonds in proteins: A) result from an oxidation of thiols. B) help to maintain the shape of proteins. C) can be broken by reduction. D) can link two cysteine amino acid residues. E) All of the above Ans: E

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920

Topic: Protein Structure 54. Which of these amino acid residues is expected to prefer the interior of a protein to the

exterior when the protein is in aqueous medium? A) Threonine B) Valine C) Serine D) Aspartic acid E) Lysine Ans: B

Topic: Protein Structure

55. A "conjugated protein" is one which: A) possesses catalytic properties. B) is a digestive enzyme. C) exists largely as an ∝-helix. D) contains unsaturated amino acids. E) contains a nonprotein group as part of the molecule. Ans: E

Topic: Peptide Sequencing, Labeling, and Synthesis

56. A pentapeptide has the molecular formula: Asp, Glu, His, Phe, Val. Partial hydrolysis of the pentapeptide gives: Val·Asp, Glu·His, Phe·Val, and Asp·Glu. What is the amino acid sequence of the pentapeptide? A) Phe·Val·Asp·Glu·His B) His·Glu·Asp·Val·Phe C) Asp·Glu·His·Phe·Val D) Phe·Val·Glu·His·Asp E) Glu·His·Phe·Val·Asp Ans: A

Topic: Peptide Sequencing, Labeling, and Synthesis

57. A heptapeptide Ala2, Glu, Phe, Pro, Tyr, Val gives labeled alanine when heated with DNFB followed by hydrolysis. On partial hydrolysis the unlabeled heptapeptide gives the following: Ala·Glu, Pro·Tyr, Ala·Val, Tyr·Ala, Val·Phe·Pro. What is the amino acid sequence of the heptapeptide? A) Ala·Phe·Pro·Tyr·Ala·Glu·Val B) Ala·Val·Phe·Pro·Tyr·Ala·Glu C) Ala·Val·Phe·Pro·Tyr·Glu·Ala D) Ala·Val·Phe·Tyr·Pro·Ala·Glu E) Val·Ala·Phe·Tyr·Pro·Ala·Glu Ans: B

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Topic: Peptide Sequencing, Labeling, and Synthesis 58. When the pentapeptide below is heated first with 2,4-dinitrofluorobenzene (and base)

and then subjected to acidic hydrolysis, which amino acid will bear the dinitrophenyl group? Leu·Val·Gly·Phe·Ile A) Leucine B) Valine C) Glycine D) Phenylalanine E) Isoleucine Ans: A

Topic: Peptide Sequencing, Labeling, and Synthesis

59. The Edman degradation uses this reagent to identify the N-terminal amino acid of a peptide or protein. A) C6H5NHNH2 B) C6H5NH2 C) C6H5N=C=S D) C6H5N=C=O E) Aminopeptidase Ans: C

Topic: Peptide Sequencing, Labeling, and Synthesis

60. Which amino acid of a polypeptide would become labeled when the polypeptide is treated with 2,4-dinitrofluorobenzene in base, even though the amino acid is not a terminal amino acid? A) Lysine B) Glycine C) Alanine D) Phenylalanine E) Leucine Ans: A

Topic: Peptide Sequencing, Labeling, and Synthesis

61. The purple color of the anion formed in the ninhydrin test for ∝-amino acids is due to: A) the attraction of the anion to a metal in a pi-complex. B) intermolecular hydrogen bonding. C) molecular vibrations. D) the highly conjugated nature of the anion. E) the color of the ninhydrin. Ans: D

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922

Topic: Peptide Sequencing, Labeling, and Synthesis 62. Which one of these amino acids does not give the usual purple color with ninhydrin?

A) Histidine B) Proline C) Tryptophan D) Leucine E) Aspartic acid Ans: B

Topic: Peptide Sequencing, Labeling, and Synthesis

63. This reagent is used to "protect" the amino group of an amino acid which is to be joined to a second amino acid by a peptide bond. A)

Cl

O

B)

C6H5 Cl

O

C)

O Cl

O

C6H5 D)

O C6H5

O

C6H5

O

E)

O Cl

O

Ans: C

Topic: Peptide Sequencing, Labeling, and Synthesis

64. Which of these is used to convert a protein into smaller, more manageable fragments for subsequent structural studies? A) Insulin B) Aminopeptidase C) Carboxypeptidase D) Trypsin E) 2,4-Dinitrofluorobenzene Ans: D

Topic: Peptide Sequencing, Labeling, and Synthesis

65. How many different tripeptides can exist, each containing one residue of glycine, one of L-threonine, and one of L-arginine? A) 2 B) 3 C) 6 D) 8 E) 9 Ans: C

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923

Topic: Peptide Sequencing, Labeling, and Synthesis 66. What use is made of dicyclohexylcarbodiimide (DCC) in peptide synthesis?

A) DCC "protects" the amino group of the intended N-terminal amino acid. B) DCC activates the carboxyl group of one amino acid so that this amino acid reacts

more readily with a second amino acid. C) DCC cleaves the blocking groups from the final peptide. D) DCC is the resin used in the automated synthesis of peptides. E) DCC removes the peptide from the resin at the conclusion of the synthesis. Ans: B

Topic: Peptide Sequencing, Labeling, and Synthesis

67. Which is an incorrect statement concerning the tetrapeptide L-arginine-L-leucine-L-cysteine-L-phenylalanine? A) This peptide would have an isoelectric point greater than 6.0. B) The peptide will be modified by mild oxidizing agents. C) Trypsin will catalyze preferentially the hydrolysis of the arginine-leucine peptide

bond. D) Hydrolysis in dilute aqueous NaOH would lead to racemization of all four amino

acids. E) All peptide bonds will be cleaved by refluxing with 6 M HCl for 24 hours. Ans: D

Topic: Stereochemistry

68. Which of these amino acids has the R configuration at the stereogenic center but, nonetheless, is an L amino acid?

CH2SH

H3N HCO2

I II III

IV V

CH2OH

H3N HCO2

CH2C6H5

H3N HCO2

CH2CO2H

H3N HCO2

CH2CH2SCH3

H3N HCO2

A) I B) II C) III D) IV E) V Ans: A

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Topic: Stereochemistry 69. Which of these amino acids cannot be described as an L amino acid?

CO2HHH2N

HNH2HO2C

CO2HH

HH2N

HNH2HO2C

OHNH2

HHO2C

I II III

IV VA) I B) II, IV and V C) I and III D) II and IV E) III and V Ans: E

Topic: Stereochemistry 70. Which of these amino acids is a D amino acid?

CO2HHH2N

HNH2HO2C

CO2HH

HH2N

HNH2HO2C

OHNH2

HHO2C

I II III

IV VA) I B) II C) III D) IV E) V Ans: E

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Topic: Stereochemistry 71. Which of these amino acids is an R amino acid?

CO2HHH2N

C6H5

HNH2HO2C

CO2HH

HH2N

HNH2HO2C

HS

I II III

IV V

NHOH

O

H

A) II and IV B) IV and V C) I and III D) V E) All of these are R amino acids Ans: B

Topic: Stereochemistry 72. Which of the following amino acids is theoretically capable of existing in

diastereomeric forms?

CO2

NH3

I

CO2

NH3

II

HOCO2

NH3

III

CO2

NH3NH2

CO2

IV V

Glycine Alanine Threonine

Leucine Proline

A) I B) II C) III D) IV E) V Ans: C

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926

Topic: Stereochemistry 73. Which amino acid is achiral?

CO2

NH3

I

CO2

NH3

II

HOCO2

NH3

III

CO2

NH3NH2

CO2

IV V

Glycine Alanine Threonine

Leucine Proline

A) I B) II C) III D) IV E) V Ans: A

SHORT ANSWER QUESTIONS

Topic: Protein Structure 74. The exact sequence of the different α-amino acids along the protein chain is called the

________________ of the protein. Ans: primary structure

Topic: Henderson-Hasselbach Equation

75. The Henderson-Hasselbach equation shows that the ________________ of an acid is the ________________ at which the acid is half-neutralized. Ans: pKa , pH

Topic: Protein Structure

76. The folding of the polyamide chain gives rise to higher levels of complexity called the _______________ and ______________ of the protein. Ans: secondary; tertiary structures

Topic: Amino Acid Structure

77. The 22 α-amino acids can be subdivided into three different types on the basis of the structures of their side chains. These three types are: ____________. Ans: neutral, acidic, basic

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927

Topic: Isoelectric Point 78. The pH at which the concentration of the zwitterionic form (dipolar form) of an amino

acid is at its highest and the concentrations of the cationic and anionic forms are equal is called the _____________. Ans: isoelectric point

Topic: Strecker Synthesis

79. Amino acids can be prepared from aldehydes by treatment with ammonia and HCN followed by hydrolysis. This method is known as the ___________. Ans: Strecker synthesis

Topic: Analysis

80. A reagent that reacts with most amino acids to give an intense purple color is called ___________. Ans: ninhydrin

Topic: Analysis

81. The most widely used method for identifying the N-terminal amino acid in a peptide chain is called the ____________. Ans: Edman degradation

Topic: Analysis

82. C-terminal amino acids can be identified through the use of _____________. Ans: digestive enzymes or carboxypeptidases

Topic: Glucose Metabolism

83. The hormone that regulates glucose metabolism is called ______________. Deficiency of this hormone is the major cause of __________. Ans: insulin; diabetes

Topic: Peptide Synthesis

84. Peptide synthesis has four basic steps. These are: Ans: protect the N-terminus, activate the carboxylic acid, react with a different amine

to form the peptide bond, deprotect the N-terminus

Topic: Protein Structure 85. The secondary structure of proteins has three basic types of folding patterns. These are:

Ans: α-helices, β-pleated sheets, turns

Topic: Enzymes 86. All reactions that occur in living cells are mediated by biological catalysts called

___________. The prevailing hypothesis for enzyme catalysis is called the ____________ hypothesis. Ans: enzymes; lock-and-key

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928

Topic: Analysis 87. One common method of analysis used to measure the approximate molecular weight of

a protein is called _____________. Ans: gel electrophoresis

Topic: Proteomics

88. The study of all proteins that are expressed in a cell at a given time is called ___________. Ans: proteomics

Topic: Anticancer Protein

89. A naturally occurring protein called ___________ acts as a tumor suppressant by coordinating a complex set of responses to changes in DNA, halting abnormal growth in normal cells. Ans: p53

Topic: Dipolar Ions

90. Draw structures to represent what happens when valine is dissolved in a strongly acidic solution (pH=0). Ans:

OHNH2

O

ONH3

OH3O+

(pH = 0) OHNH3

O

Valine Dipolar ion Cationic form

Topic: Dipolar Ions 91. Draw structures to represent what happens when valine is dissolved in a strongly basic

solution (pH=14). Ans:

OHNH2

O

ONH3

OOH−

(pH = 14)O

NH2

O

Valine Dipolar ion Anionic form

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Chapter 24

929

Topic: Dipolar Ions 92. Draw structures to represent what happens when lysine is dissolved in a strongly acidic

solution (pH=0). Ans:

OHNH2

O

ONH2

O

OHNH3

O

Lysine Dipolar ion

Cationic form

H2N H3N

H3O+

(pH = 0)

H3N

Topic: Dipolar Ions 93. Draw structures to represent what happens when lysine is dissolved in a strongly basic

solution (pH=14). Ans:

OHNH2

OH2N

ONH2

OH3N

ONH2

OH2N

Lysine Dipolar ion

Anionic form

OH−

(pH = 14)

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Chapter 24

930

Topic: Synthesis and Reactions 94. What is the final product formed when potassium phthalimide is subjected to the

following reaction sequence? Give structural details of all significant intermediates, including stereochemistry, as applicable.

N K

O

O

i. BrCH(CO2H5)2ii. NaOEt, C6H5CH2Briii. NaOHiv. HCl, heat

?

Ans: N K

O

O

BrCH(CO2H5)2

NaOHNH

O

CO2

C6H5

CO2

CO2

CO2H

CO2H H2NC6H5

CO2H

N

O

O

CO2Et

CO2Et

N

O

O

CO2Et

CO2Et

CH2C6H5

HCl, heat

+ CO2 +

DL-Phenylalanine

NaOEtC6H5CH2Br

Topic: Strecker Synthesis 95. Give the structure of the aldehyde which, upon treatment with HCN and ammonia,

followed by heating with aqueous acid, would afford racemic tryptophan. What is this strategy for the synthesis of α-amino acids called? Ans: This is called the Strecker synthesis

NH

O

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931

Topic: Amino Acid Synthesis 96. What is the final product formed via the following reaction sequence? Give structural

details of all significant intermediates.

HNCO2Et

CO2EtO

i. CH2=CHCN, NaOEt, EtOHii. conc HCl, reflux

?

Ans: HN

CO2Et

CO2EtO

H2N

CO2H

CO2H

HNCO2Et

CO2EtO

CH2CH2CN

CH3CO2H + CO2 +

DL-Glutamic acid

CH2=CHCNNaOEt, EtOH

conc HClreflux

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932

Topic: Peptide Synthesis 97. Suggest a reasonable strategy for the synthesis of the dipeptide Leu-Phe, using

established protocol for peptide synthesis. Ans:

H3N O

O O Cl

O

O NH

O HN

OOH

O

H3NHN

OO

O

(Phe)

H3N O

O

O NH

OO

O

O NH

OO

O

OEt

O

Leu-Phe

OH , 25oC

i. Et3Nii. ClCO2Et

H2,Pd

+ + CO2

Leu

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933

Topic: Peptide Structure 98. Draw the structure of the following tripeptide (starting with the N-terminal residue and

ending with the C-terminal residue), showing stereochemical details: Gly-Phe-Met Ans:

Gly-Phe-Met

H3N

HN

NH

OHH

O H

O

O

H

S

Topic: Peptide Structure

99. Draw the structure of the following tripeptide (starting with the N-terminal residue and ending with the C-terminal residue), showing stereochemical details: Ala-Ser-Leu Ans:

H3N

HN

NH

OHH3C

O H

O

O

H

HO

Ala-Ser-Leu

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934

Topic: Peptide Structure 100. Draw the structure of the following tripeptide (starting with the N-terminal residue and

ending with the C-terminal residue), showing stereochemical details: Val-Trp-Asn Ans:

H3N

HN

NH

OH

O H

O

O

H

Val-Trp-Asn

NH

ONH2

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Chapter 25

1

MULTIPLE CHOICE QUESTIONS

Topic: The Double Helix 1. What is the secondary structure of DNA?

A) An alpha-helix B) A pleated sheet C) A flat sheet D) A double helix E) A random coil Ans: D

Topic: The Double Helix

2. Which is an incorrect statement concerning the DNA double helix? A) The sugar-phosphate backbone is on the outside of the helix and the base pairs are

on the inside. B) The two strands are identical but proceed in opposite directions. C) Hydrogen bonding holds together the two strands. D) Only purine-pyrimidine base pairs can be accommodated. E) The sugar-phosphate backbone is completely regular. Ans: B

Topic: The Double Helix

3. Which is an incorrect statement concerning the DNA double helix? A) The sugar-phosphate backbone is on the inside of the helix and the base pairs are

on the outside. B) The two strands are identical but proceed in opposite directions. C) The two strands are linked by glycosidic bonds. D) Two of the above statements are incorrect. E) All of the above statements are incorrect. Ans: E

Topic: DNA Structure

4. Which is an incorrect statement concerning DNA structure? A) The base and the phosphate units are linked by phosphodiester bonds. B) The sugar and the phosphate units are linked by hydrogen bonds. C) The base and the sugar units are linked by β-N-glycosidic bonds. D) Two of the above statements are incorrect. E) All of the above statements are incorrect. Ans: D

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2

Topic: DNA Structure 5. Which is a correct statement concerning DNA structure?

A) The base and the phosphate units are linked by hydrogen bonds. B) The sugar and the phosphate units are linked by phosphodiester bonds. C) The base and the sugar units are linked by β-N-glycosidic bonds. D) Two of the above statements are correct. E) None of the above statements are correct. Ans: D

Topic: DNA Structure

6. The analytical data for DNA samples which led to generalizations such as (%G + %A) ≈ (%C + %T) came from the research of what individual? A) James Watson B) Francis Crick C) Edwin Chargaff D) Arthur Kornberg E) Maurice Wilkins Ans: C

Topic: DNA Structure

7. Which bases pair in DNA by hydrogen bonding? A) Cytosine and thymine B) Cytosine and uracil C) Adenine and guanine D) Adenine and thymine E) Adenine and uracil Ans: D

Topic: DNA Structure

8. In DNA, thymine can pair via hydrogen bonding to _________? A) Cytosine B) Uracil C) Adenine D) Guanine E) Deoxyribose Ans: C

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Chapter 25

3

Topic: DNA Structure 9. In DNA, cytosine can pair via hydrogen bonding to _________?

A) Deoxyribose B) Uracil C) Adenine D) Guanine E) All of the above Ans: D

Topic: DNA Structure

10. In DNA, adenine can be linked to _________ . A) Deoxyribose via β-N-glycosidic bonds B) Uracil via hydrogen bonds C) Phosphate via phosphodiester bonds D) Guanine via amide bonds E) All of the above Ans: A

Topic: RNA Structure

11. In RNA, adenine can be linked to _________ . A) Deoxyribose via β-N-glycosidic bonds B) Uracil via hydrogen bonds C) Phosphate via phosphodiester bonds D) Guanine via amide bonds E) All of the above Ans: B

Topic: The Double Helix

12. In DNA, the lactim form of guanine will pair with which base? A) Cytosine B) Adenine C) Uracil D) Thymine E) No pairing is possible. Ans: D

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Chapter 25

4

Topic: The Double Helix 13. Consideration of tautomerism in guanine suggests that it can exist in lactam and lactim

forms. The form that is typically found in DNA is __________, typically pairs with _____________, while the other form is likely to pair with __________, leading to the possible spontaneous mutations. A) Lactam, cytosine, thymine B) Lactam, cytosine, adenine C) Lactim, cytosine, thymine D) Lactam, uracil, cytosine E) Lactim, cytosine, thymine Ans: A

Topic: The Double Helix

14. Consider the effect of nitrous acid on the adenine residue of a DNA strand. The product now resembles __________, and is likely to pair with __________, instead of with ___________, leading to the possible mutations. A) guanine, cytosine, thymine B) thymine, cytosine, guanine C) thymine, guanine, cytosine D) uracil, cytosine, guanine E) cytosine, guanine, thymine Ans: A

Topic: The Double Helix

15. Which is the predominant tautomeric form of cytosine when it is present in DNA?

N

N

NH2

O

N

N

NH

O

HN

N

NH

O

I II III A) I B) II C) III D) None of these E) I, II and III are present in approximately equal amounts. Ans: A

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Chapter 25

5

Topic: The Double Helix 16. The following structure represents the less common (in DNA, at least) tautomeric form

of __________.

N

N

OH

O

H3C

A) Cytosine B) Thymine C) Adenine D) Guanine E) Uracil Ans: B

Topic: DNA Structure

17.

Which is the predominant tautomeric form of guanine when it is present in DNA?

NH

NNH

NO

NH2

N

NNH

NOH

NH2

NH

NN

HN

O

NH2

N

NN

HN

OH

NH2

N

NH

NH

NO

NH2

I II III

VIVA) I B) II C) III D) IV E) V Ans: A

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Chapter 25

6

Topic: DNA Structure 18.

Which is the predominant tautomeric form of adenine when it is present in DNA?

N

NH

NH

NNH2

CH3

N

NNH

NNH2

N

NN

HN

NH2

O

N

NN

HN

NH2

NH

NNH

NNH

I II III

VIVA) I B) II C) III D) IV E) V Ans: B

Topic: Sequencing

19. In DNA sequencing, what is used to convert DNA molecules into smaller, more manageable fragments? A) DNA polymerase B) Dilute HCl C) Trypsin D) Chymotrypsin E) Restriction endonucleases Ans: E

Topic: Sequencing

20. Separation of the fragments produced in the chemical sequencing of a DNA segment is achieved by the use of which of these techniques? A) Column chromatography B) Fractional distillation C) Thin layer chromatography D) Gas chromatography E) Gel electrophoresis Ans: E

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Chapter 25

7

Topic: Sequencing 21. If the base sequence along a segment of DNA were G—C—C—A—T, what would be

the base sequence of messenger RNA synthesized from this sequence? A) G—C—C—A—T B) C—G—G—T—A C) C—G—G—U—A D) G—C—C—A—U E) A—T—T—G—C Ans: C

Topic: Sequencing

22. The antisense nucleotide G—A—C—T—C, could be synthesized via a __________ template on ________? A) T—C—A—G—A , RNA B) C—T—G—A—G, DNA C) C—T—G—A—G, RNA D) G—A—C—T—U, DNA E) A—G—T—C—T, RNA Ans: B

Topic: Sequencing

23. If the base sequence along a segment of DNA were T—C—G—T—A, what would be the antisense oligonucleotide synthesized from this sequence? A) G—C—C—A—T B) C—G—G—T—A C) U—G—C—U—T D) A—G—C—A—U E) A—G—C—A—T Ans: E

Topic: Sequencing

24. If the base sequence along a segment of DNA were G—C—C—A—T, what would be the base sequence of messenger RNA synthesized from this sequence? A) C—U—U—T—A B) C—G—G—T—A C) C—G—G—U—A D) G—C—C—A—U E) A—T—T—G—C Ans: C

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8

Topic: Sequencing 25. During translation, the segment on the mRNA that corresponds to the base sequence

C—G—A along a gene segment of DNA, would bind to the anticodon __________ on a tRNA. A) A—U—C B) G—C—U C) U—T—C D) G—C—T E) C—G—A Ans: E

Topic: Assorted Reactions

26. Complete hydrolysis of adenylic acid would yield which of these? A) Adenosine and a phosphate ion B) Adenine, D-ribose, and a phosphate ion C) Adenine and D-ribose D) Adenine and 2-deoxy-D-ribose E) A pyrimidine, a pentose, and a phosphate ion Ans: B

Topic: Nucleotide Synthesis

27. Supply the missing reagent in the following synthesis.

O

OHOH

baseHO

O

OO

baseHO

H3C CH3

H3O++ ?

A) (CH3)2C=O B) HOCH2CH2OH C) CH3CHOHCH3 D) CH3CCl2CH3 E) CH3CHClCH3 Ans: A

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Chapter 25

9

Topic: Nucleotide Synthesis 28. Supply the missing reagent(s) in the synthesis below.

O

OO

baseHO

H3C CH3

pyridineO

OO

baseO

H3C CH3

P(OCH2C6H5)2O

+ ?

A) PO4

-3 and C6H5CH2OH B) PO4

-3 and C6H5CH2Cl C) O

P(OCH2C6H5)2

Cl D) C6H5CH3 + POCl3 E) C6H5CH2OH + H3PO4 Ans: C

Topic: Assorted Reactions

29. The synthesis of adenosine by the reaction shown below likely occurs by what reaction mechanism?

N

NN

N

Cl

N

NN

N

NH2

NH3

R R

( R = ribofuranosyl )A) An SN2 reaction B) An SNAr reaction C) An elimination-addition reaction D) An SN1 reaction E) An E2 reaction Ans: B

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Chapter 25

10

Topic: Assorted Reactions 30. The action of nitrous acid on 5-methylcytosine produces which nitrogen base?

N

NH

NH2

O

H3C

5-methylcytosine A) Adenine B) Guanine C) Cytosine D) Thymine E) Uracil Ans: D

Topic: Assorted Reactions

31. An RNA nucleoside will undergo hydrolysis in dilute acid to yield which of the following? A) 2-Deoxy-D-ribose and a heterocyclic base B) 2-Deoxy-D-ribose, a heterocyclic base, and phosphate ion C) D-Ribose and a heterocyclic base D) D-Ribose, a heterocyclic base, and phosphate ion E) D-Ribose and phosphate ion Ans: C

Topic: Assorted Reactions

32. Which are the products of hydrolysis of a RNA nucleotide? A) D-Ribose, adenine B) D-Ribose, guanine, phosphate C) D-Ribose, thymine, phosphate D) 2-Deoxy-D-ribose, cytosine, phosphate E) 2-Deoxy-D-ribose, adenine Ans: B

Topic: Assorted Reactions

33. Hydrolysis of DNA from various species gives which of the following results? A) The mole percentage of adenine is approximately equal to that of thymine. B) The mole percentage of cytosine is approximately equal to that of guanine. C) The total mole percentage of purines is approximately equal to that of

pyrimidines. D) All of the above E) None of the above Ans: D

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Chapter 25

11

Topic: Codons and Anticodons 34. What is the transfer RNA anticodon for the messenger RNA codon, G—C—A?

A) T—A—T B) G—U—T C) G—C—A D) A—C—G E) C—G—U Ans: E

Topic: Codons and Anticodons

35. Where is the sequence of bases termed an "anticodon" found? A) mRNA B) tRNA C) rRNA D) DNA E) Polysomes Ans: B

Topic: Codons and Anticodons

36. If a tRNA anticodon is GUC, what was the original base sequence in DNA? A) GUC B) GTC C) CAG D) GAC E) CTG Ans: B

Topic: Codons and Anticodons

37. Which is the messenger codon which calls for the initiation of protein synthesis? A) AUG B) GUA C) UAG D) AUC E) CAC Ans: A

Topic: Codons and Anticodons

38. Concerning the genetic code, which of the following is an incorrect statement? A) Not all codons specify amino acids. B) There are a total of 64 different triplets. C) For each amino acid there are the same number of codons. D) The triplet codons are incorporated in messenger RNA. E) The triplet AUG is a "start" codon. Ans: C

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Chapter 25

12

Topic: Nucleic Acid Structure 39. The monomeric units of nucleic acids are which of these?

A) D-ribose or 2-deoxy-D-ribose B) Phosphate ions C) Purines D) Nucleosides E) Nucleotides Ans: E

Topic: Assorted Definitions

40. The primary function of nucleic acids is: A) the catalysis of biochemical reactions. B) the regulation of reactions that occur in the body. C) the preservation, transcription and translation of information. D) the acid-catalyzed hydrolysis of nucleotides. E) the neutralization of nucleic bases. Ans: C

Topic: Nucleic Acid Structure

41. A nucleotide unit is composed of: A) a five carbon monosaccharide. B) a phosphate group. C) a heterocyclic base. D) an amino acid. E) A), B) and C) Ans: E

Topic: Nucleic Acid Structure

42. A purine: A) contains four nitrogens in the ring system. B) is bicyclic. C) can participate in hydrogen bonding. D) is a heterocyclic base. E) All of the above Ans: E

Topic: Nucleic Acid Structure

43. In a nucleotide unit, the components are sequentially linked: A) monosaccharide--phosphate--heterocyclic base. B) amino acid--monosaccharide--phosphate. C) phosphate--monosaccharide--heterocyclic base. D) monosaccharide--amino acid--phosphate. E) heterocyclic base--phosphate--monosaccharide. Ans: C

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Chapter 25

13

Topic: Nucleic Acid Structure 44. Which of the following is not a pyrimidine?

A) Cytosine B) Thymine C) Guanine D) Uracil E) All of the above are pyrimidines. Ans: C

Topic: Nucleic Acid Structure

45. The hydrogen bonding for the base pairs of DNA is between: A) amide carbonyl and -NH2. B) amide N-H and cyclic amine nitrogens. C) alcohols and carbonyls. D) All of these E) Only A) and B) Ans: E

Topic: Nucleic Acid Structure

46. Which heterocyclic base found in RNA does not occur in DNA? A) Guanine B) Thymine C) Cytosine D) Uracil E) Adenine Ans: D

Topic: Assorted Definitions

47. The formation of a new DNA molecule which is an exact copy of a pre-existing one is designated by what term? A) Duplication B) Transcription C) Translation D) Replication E) Reproduction Ans: D

Topic: DNA Mutation

48. Nitrous acid is a suspected mutagen because of its reaction with: A) amine groups. B) monosaccharides. C) phosphates. D) alcohols. E) ketones. Ans: A

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Chapter 25

14

Topic: Protein Synthesis 49. The synthesis of proteins according to "the central dogma of molecular genetics" would

require: A) replication then translation. B) translation then replication. C) replication then transcription. D) transcription then translation. E) Any of these Ans: D

Topic: Protein Synthesis

50. Which is the initial N-terminal amino acid in the developing polypeptide in bacteria? A) Cysteine B) Methionine C) N-Formylmethionine D) Glycine E) Alanine Ans: C

Topic: Miscellaneous

51. Which of these has the smallest molecular weight? A) rRNA B) mRNA C) tRNA D) DNA Ans: C

Topic: Miscellaneous

52. Which statement concerning the monosaccharide portion of nucleotides is true in every case? A) The monosaccharide is in the pyranose form. B) The linkage to phosphate is at carbon #3. C) The heterocyclic base is attached to carbon #1 of the monosaccharide. D) The monosaccharide - nitrogen base linkage is ∝. E) The monosaccharide is 2-deoxy-D-ribose. Ans: C

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Chapter 25

15

Topic: Miscellaneous 53. Relatively short synthetic strands of DNA complementary to certain portions of a gene

are known as: A) antisense nucleotides. B) templates. C) palindromes. D) endonucleases. E) polymerases. Ans: A

Topic: Transcription

54. The anticodon is part of A) mRNA B) rRNA C) tRNA D) DNA E) None of these Ans: C

Topic: Transcription

55. The codon is part of A) mRNA B) rRNA C) tRNA D) DNA E) None of these Ans: A

Topic: Transcription

56. The codon consists of A) A sequence of three bases B) A sequence of three amino acids C) A sequence of three purines D) A sequence of three pyrimidines E) None of these Ans: A

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Chapter 25

16

Topic: Transcription 57. Specific amino acids attach to the arm of a tRNA that ends in __________, via a(n)

_________ bond. A) CCG, ester B) ACG, ether C) CCA, glycosidic D) ACA, amide E) CCA, ester Ans: E

Topic: Transcription

58. The time required to synthesize a protein depends on the number of amino acid residues it contains. A rough estimate is that each ribosome can cause _________ peptide bonds to be formed per minute. A) 30 B) 50 C) 100 D) 150 E) 200 Ans: D

Topic: Polymerase Chain Reaction

59. Which of the following statements about the polymerase chain reaction are true? A) It generates a large number of copies of DNA B) It polymerizes the short oligonucleotide strands formed during biosynthesis C) It catalyzes the formation of mRNA D) It needs a minuscule sample of DNA E) Two of the above Ans: E

Topic: Polymerase Chain Reaction

60. Which of the following is not a valid application of the PCR (polymerase chain reaction) ? A) Semen analysis in forensic investigations B) Evolutionary biology C) Detection of cytomegalovirus D) Prenatal diagnosis of sickle cell anemia E) All of these are valid applications of the PCR Ans: E

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Chapter 25

17

SHORT ANSWER QUESTIONS

Topic: Protein Synthesis 61. The molecular archive of instructions for protein synthesis is called ______. The

molecules that transcribe and translate these instructions are called ______. Ans: DNA; RNA

Topic: DNA Structure

62. The four bases that make up the DNA “ladder” are: ____________. Ans: adenine, cytosine, guanine, and thymine

Topic: RNA Structure

63. The four bases found in RNA are: _________. Ans: adenine, cytosine, guanine, and uracil

Topic: Miscellaneous

64. Each section of DNA that codes for a particular protein is called a _______. Ans: gene

Topic: Miscellaneous

65. Amino acids bear the same relation to proteins as __________ do to nucleic acids. Ans: nucleotides

Topic: Miscellaneous

66. While proteins are made up of amino acids connected by amide bonds, nucleic acids are made up of nucleotides connected by __________. Ans: phosphate ester linkages

Topic: DNA Structure

67. The secondary structure of DNA was proposed by Watson and Crick to be a ___________________. Ans: double helix

Topic: DNA Structure

68. In the DNA double helix, two strands of nucleic acids are held together by _____________. Ans: hydrogen bonds

Topic: DNA Structure

69. In the DNA base pairs, adenine always bonds with _________ and cytosine with __________. Ans: thymine; guanine

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Chapter 25

18

Topic: DNA Structure 70. The backbone of DNA is made up of __________.

Ans: sugars and phosphates

Topic: Miscellaneous 71. A chemical that causes mutations in DNA is called a _________.

Ans: Mutagen

Topic: Protein Synthesis 72. Protein synthesis requires that two major processes take place. The first takes place in

the cytoplasm involving messenger RNA (mRNA) and is called ___________. The second involves two other types of RNA: __________ and ____________. Ans: transcription; ribosomal RNA [rRNA]; transfer RNA [tRNA]

Topic: Protein Synthesis

73. The anticodon is a specific sequence of ____________, found on the ___________, which allows it to bind to the ____________, of _____________. Ans: three bases, tRNA, codon, mRNA

Topic: RNA

74. The molecular weight of tRNA is _________, compared with mRNA or rRNA; consequently, the solubility of tRNA is __________. Ans: low, high

Topic: RNA

75. The function of tRNA is ___________. Ans: to transport amino acids to specific areas on the mRNA bound to the ribosome

Topic: Triplet Code

76. Explain why 3 bases (triplet code) are needed in the genetic code to unambiguously identify each amino acid. Ans: There are only four bases and 20 amino acids; thus, each base could uniquely

code for only 4 amino acids. A set of two bases would uniquely code for (42) , i.e., 16 amino acids, still not quite enough. However, if each amino acid were to be coded via a set of three bases, then there could be 64 possible combinations, allowing for redundancies and certain necessary “punctuation” codes, such as start/stop codes, etc.

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Chapter 25

19

Topic: DNA Structure 77. Draw structures to represent the hydrogen bonding between adenine and thymine.

Ans:

NN

N

N N

NN

O

O

HH

H

..:

adenine thymine

:

Topic: DNA Structure

78. Draw structures to represent the hydrogen bonding between cytosine and guanine. Ans:

guanine cytosine

NN

N

N

NN

N

O

H

O

NH

H

:..

: ..

HH

:

Topic: DNA Structure

79. Draw structures to represent the hydrogen bonding between adenine and uracil. Ans:

NN

N

N N

NN

O

O

HH

H

..:

adenine uracil

:

Topic: DNA Structure

80. Draw structures to represent the bonding between deoxyribose and thymine. Ans:

O

HOH

HO

N

N

O

O

Hthymine

deoxyribose

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Topic: DNA Structure 81. Draw structures to represent the bonding between ribose and uracil.

Ans:

O

OHOH

HO

N

N

O

O

Huracil

ribose

Topic: DNA Structure 82. Draw the structures to represent what is likely to happen when cyclic AMP (3’,5’-cyclic

adenylic acid) reacts with aqueous sodium hydroxide, briefly explaining your rationale. Ans:

O

OHO

O

PO

O

N

NN

N

NH2

O

OHOHOP

O

HO

HO

N

NN

N

NH2

NaOHH2O

cyclic AMP 3'-adenylic acid

5'

3'

The reaction appears to follow an SN2 mechanism, with nucleophilic attack by OH− at the primary 5’- position to afford 3’-adenylic acid (rather than at the secondary 3’- position, which would yield 5’-adenylic acid).

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Topic: Nucleotide Synthesis 83. Suggest a reasonable strategy for the specific phosphorylation of the 5’ –OH group of a

nucleoside. Ans: In order for phosphorylation to occur specifically at the 5’ OH, the 2’- and 3’- OH

groups must first be protected.

OP(OCH2C6H5)2

Clpyridine

O

OO

baseO

H3C CH3

P(OCH2C6H5)2O

O

OO

baseHO

H3C CH3

O

OHOH

baseO

P(OCH2C6H5)2O

O

OHOH

baseHO

acetoneH3O+

i. H3O+, H2O

ii. H2, Pd

Topic: Tautomerism, Mutation 84. Draw the structures of two tautomeric forms of guanine, one a lactam, the other a

lactim. Explain the possible involvement of the lactim form in causing spontaneous mutation during replication. Ans: The lactim form resembles adenine and might pair with thymine instead of

cytosine, causing the first error in the new DNA strand being synthesized. This mistake, if uncorrected, can then be passed on to the next strand being synthesized from this “mutated” strand, by introducing an adenine residue, where there should be a guanine residue.

NN

N

N

HH

O

NH

H

:..

NN

N

N

H

OH

NH

H

:

lactam(likely to pair with cytosine)

lactim(likely to pair with thymine)

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85. What product is likely to be formed from the reaction between an adenine residue on a

nucleotide and nitrous acid? Explain the possible involvement of the product of this reaction in causing spontaneous mutation during replication. Ans: The product resembles a guanine nucleotide, thus might pair with cytosine instead

of thymine, causing the first error in the new DNA strand being synthesized. This mistake, if uncorrected, can then be passed on to the next strand being synthesized from this “mutated” strand, by introducing a guanine residue, where there should be an adenine residue.

NN

N

N

R

NH2

HNO2 NHN

N

N

R

O

adenine nucleotide(pairs with thymine)

hypoxanthine nucleotide(likely to pair with cytosine)