Select the correct statements for Hofmann bromamide degradation reaction:
(A) Used to prepare primary amines
(B) Amides are treated with bromine in aqueous solution.
(C) NaOH is used in this reaction.
(D) HCl is used in this reaction
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (B) and (C) only
In the Hofmann bromamide degradation, an amide is treated with bromine in an aqueous or ethanolic solution of sodium hydroxide. An alkyl or aryl group migrates from the carbonyl carbon to nitrogen, and the primary amine formed has one carbon atom less than the amide; the lost carbon leaves as carbonate:
\( \displaystyle \ce{R-CO-NH2 + Br2 + 4NaOH -> R-NH2 + Na2CO3 + 2NaBr + 2H2O} \)
For example, ethanamide gives methanamine:
\( \displaystyle \ce{CH3CONH2} \xrightarrow{\ce{Br2}/\ce{NaOH}} \ce{CH3NH2} \)
(A) Used to prepare primary amines — Correct. The product is always a primary amine, \( \ce{R-NH2} \).
(B) Amides are treated with bromine in aqueous solution. — Correct. Bromine is used in an aqueous (or ethanolic) alkaline solution.
(C) NaOH is used in this reaction. — Correct. Four moles of NaOH are used per mole of amide; the base removes protons from the amide nitrogen and takes up the carbon as sodium carbonate.
(D) HCl is used in this reaction — Incorrect. The reaction needs a strongly basic medium; an acid would neutralise the NaOH and stop it.
NCERT (2026-27 edition):
Hoffmann Bromamide Degradation Reaction
