Question

Identify false statement from following regarding preparation of amines by Hofmann degradation method.

• A. It is useful to convert amides to primary amines.
• B. In this -CO-group is reduced to \(-\text{CH}_2-\) group.
• C. Molar mass of the amine obtained is always less than the amide.
• D. The reagent used is \(\text{Br}_2\) and \(\text{KOH}_{(aq)}\) .

Hint:

Hofmann bromamide reaction removes the carbonyl carbon as carbonate; it does not reduce it.

Answer 1

The Correct Option is B

Step 1: Recall the mechanism:
Amide, then N-bromoamide, then isocyanate ($\text{R-N=C=O}$), then hydrolysis to amine and $\text{CO}_2$ (taken up by KOH as carbonate).

Step 2: Judge statement (B):
The $\text{C=O}$ carbon leaves as carbonate rather than turning into $\text{CH}_2$. The other three statements match the reaction. So (B) is false.

Final Answer:
Statement (B). \[ \boxed{\text{(B)}} \]