What is the product formed when acetamide is reduced with lithium aluminium hydride?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Ethylamine
Lithium aluminium hydride reduces the C=O group of an amide to CH2; the nitrogen stays, so an amide gives an amine with the same number of carbon atoms.
\( \displaystyle \ce{CH3CONH2} \xrightarrow[\text{(ii) }\ce{H2O}]{\text{(i) }\ce{LiAlH4}} \ce{CH3CH2NH2} \)
Acetamide has two carbons, so the product is the two-carbon amine ethylamine (ethanamine).
Why the other options are incorrect
Option (1) Methylamine — Incorrect. It has one carbon fewer; that loss of a carbon happens in the Hoffmann bromamide reaction (Br2 and NaOH), not in LiAlH4 reduction.
Option (3) Ethanol — Incorrect. The reduction removes the oxygen and keeps the nitrogen, so the product is an amine, not an alcohol.
Option (4) No reaction — Incorrect. Amides are reduced by LiAlH4; this is a standard method of preparing amines.
NCERT (2026-27 edition):
9.4 Preparation of Amines – “4. Reduction of amides
The amides on reduction with lithium aluminium hydride yield amines.”