: 180
Both methods prepare pure primary amines, but they differ in scope and mechanism.
Gabriel: Uses phthalimide + RX (SN2). Product has same carbons as RX. Cannot make ArNH2 (aryl halide no SN2). Can make benzylamine (benzyl halide is SN2). Doesn't work for 2°/3°.
Hofmann bromamide: Uses RCONH2 + Br2/NaOH. Product has one fewer carbon than amide. Works for both aliphatic and aromatic amides. Benzamide -> aniline. Mechanism involves 1,2-alkyl shift.
When to use which: If you have an alkyl halide and want the corresponding 1° amine -> Gabriel. If you need to descend the homologous series (lose a carbon) or make an aromatic amine from its amide -> Hofmann.
JEE trap: "Can Gabriel synthesis prepare aniline?" Answer: No (ArX no SN2). "Can Hofmann prepare aniline?" Answer: Yes (from benzamide). "Can Gabriel prepare benzylamine?" Answer: Yes (C6H5CH2X is SN2-reactive).