COAS Chemistry 2 Teacher Resources Original material © Cambridge University Press 2005, 2007, 2009 1

2 Marking scheme: Worksheet 2 1 a The attacking species is an electron-pair receiver. [1]

b The attacking species replaces a species on the attacked molecule. [1] c nitrating mixture of nitric acid and sulfuric acid [1]

both concentrated [1] d

curly arrow starts at the delocalised π electrons and finishes on the nitrogen atom in NO2

+ [1] correct intermediate [1] curly arrow goes from C–H bond back into ring. [1]

2 a correct equation/diagram for production of Br+ ion, using AlBr3 or FeBr3 as catalyst [1]

b

curly arrow goes from the delocalised electrons to Br+ [1] correct intermediate [1]

c curly arrow goes from C–H bond back into ring [1]

d FeBr3 or AlBr3 catalyst regenerated [1]

3

The intermediate has four π electrons; [1]

benzene has six π electrons; [1] the π electrons are delocalised over five carbon atoms in the intermediate; [1] the π electrons are delocalised over all six carbon atoms in benzene. [1]

2 Marking scheme: Worksheet 2

COAS Chemistry 2 Teacher Resources Original material © Cambridge University Press 2005, 2007, 2009 2

4 a [1] b curly arrow from benzene [1]

correct dipole alignment on I–Cl [1] correct intermediate [1] curly arrow from hydrogen [1] correct structure for iodobenzene [1] and HCl [1]