JEE Main · 2026 · 02 Apr 2026 · Shift 2 · Compounds Containing Nitrogen

Bromination of 1-ethyl-4-nitrobenzene places bromine ortho to the activating ethyl group and meta to the nitro group, so A is 2-bromo-1-ethyl-4-nitrobenzene. Tin and HCl reduce the nitro group to an amine (B), which is diazotised at $273$--$278$ K to the diazonium salt (C); warming with ethanol replaces the diazonium group by hydrogen (D), leaving 1-bromo-2-ethylbenzene. Oxidation of the benzylic ethyl chain by $\mathrm{KMnO}{}_4/\mathrm{KOH}$ followed by acidification turns it into a carboxyl group, so E is 2-bromobenzoic acid. Compound A is 2-bromo-1-ethyl-4-nitrobenzene and compound E is 2-bromobenzoic acid.