Identify D in this reaction:

The correct answer is Option (3) → 3-bromoaniline (m-bromoaniline)

The sequence turns a carboxylic acid into an amine with one carbon less: acid → acid chloride → amide → amine. The last step is the Hoffmann bromamide degradation, in which the aryl group moves from the carbonyl carbon to nitrogen and the carbonyl carbon is lost as carbonate.

First, thionyl chloride converts 3-bromobenzoic acid into the acid chloride (B); \( \ce{SO2} \) and HCl escape as gases:

    \( \displaystyle \ce{BrC6H4COOH + SOCl2 -> BrC6H4COCl + SO2 + HCl} \)

Next, ammonia replaces –Cl by –\( \ce{NH2} \) (nucleophilic acyl substitution) to give the amide (C):

    \( \displaystyle \ce{BrC6H4COCl + 2NH3 -> BrC6H4CONH2 + NH4Cl} \)

Finally, \( \ce{Br2} \) with NaOH degrades the amide to the primary amine (D):

    \( \displaystyle \ce{BrC6H4CONH2 + Br2 + 4NaOH -> BrC6H4NH2 + Na2CO3 + 2NaBr + 2H2O} \)

The ring bromine stays at the meta position throughout, and –\( \ce{NH2} \) takes the place of –COOH, so D is 3-bromoaniline.

Why the other options are incorrect

• Option (1) 2-bromobenzenesulphonamide — Incorrect. A sulphonamide needs a sulphonyl chloride (–\( \ce{SO2Cl} \)) and \( \ce{NH3} \); \( \ce{SOCl2} \) does not put sulphur on the ring, and the Br has also moved to the ortho position.

• Option (2) 3-aminobenzoic acid — Incorrect. It keeps the –COOH and has lost the Br; the sequence removes the carboxyl carbon and leaves the C–Br bond in place.

• Option (4) 4-bromobenzamide — Incorrect. An amide is C, not D, and in the wrong (para) position; \( \ce{Br2} \)/NaOH converts the amide further.

NCERT (2026-27 edition):
Hoffmann Bromamide Degradation Reaction – “Hoffmann developed a method for preparation of primary amines by treating an amide with bromine in an aqueous or ethanolic solution of sodium hydroxide. In this degradation reaction, migration of an alkyl or aryl group takes place from carbonyl carbon of the amide to the nitrogen atom. The amine so formed contains one carbon less than that present in the amide.”