Which of the following reagents is most suitable for the conversion of an aliphatic primary amine into an alkyl isocyanide?

Solution

1. Primary amines react with ${\text{CHCl}}_3$ and $\text{KOH}$ to form isocyanides, known as the carbylamine reaction.
2. The reaction proceeds via the formation of dichlorocarbene, ${\text{:CCl}}_2$.
3. This is a characteristic test for primary amines.
4. Hence the answer is (A).