| Date | May 2010 | Marks available | 4 | Reference code | 10M.3.hl.TZ1.G3 |
| Level | HL | Paper | 3 | Time zone | TZ1 |
| Command term | Identify and Name | Question number | G3 | Adapted from | N/A |
Question
Methylbenzene can be prepared from benzene and iodomethane.
Methylbenzene reacts when heated with a mixture of concentrated sulfuric acid and concentrated nitric acid.
(i) Name the major organic products formed.
(ii) Identify the electrophile in this reaction and explain how it is formed.
Markscheme
(i) 1-methyl-2-nitrobenzene and 1-methyl-4-nitrobenzene;
Accept 2-methylnitrobenzene and 4-methylnitrobenzene.
Accept 2-nitromethylbenzene and 4-nitromethylbenzene.
Accept o-methylnitrobenzene and p-methylnitrobenzene.
(ii) \({\text{NO}}_2^ + \) / nitronium ion;
the (concentrated) sulfuric acid protonates the nitric acid /
\({\text{HN}}{{\text{O}}_3} + {{\text{H}}_2}{\text{S}}{{\text{O}}_4} \to {{\text{H}}_2}{\text{NO}}_3^ + + {\text{HSO}}_4^ - \);
the \({{\text{H}}_{\text{2}}}{\text{NO}}_3^ + \) formed loses water / \({{\text{H}}_2}{\text{NO}}_2^ + \to {{\text{H}}_2}{\text{O}} + {\text{NO}}_2^ + \);
Accept HNO3 + H2SO4 \( \to \) NO2+H2O + H2SO4– for the second and third points.
Examiners report
Candidates often named the products but had difficulty in the formation of the electrophile. The charge for \({\text{NO}}_2^ + \) was often omitted.
