Question

Aniline on heating with ‘X’ in the presence of KOH gives a product with very bad smell. Which of the following is ‘X’?

• A. CH$_3$Cl
• B. CHCl$_3$
• C. CH$_2$Cl$_2$
• D. C$_2$H$_5$Cl

Hint:

The carbylamine test is specific for \textbf{primary amines} and produces foul-smelling isocyanides.

Answer 1

The Correct Option is B

Step 1: Recall the carbylamine reaction. Primary amines on heating with chloroform (CHCl$_3$) and alcoholic KOH form isocyanides.
Step 2: Aniline is a primary aromatic amine.
Step 3: When aniline reacts with CHCl$_3$ and KOH, it forms phenyl isocyanide, which has an extremely foul smell.
Step 4: The reaction is: \[ \text{C}_6\text{H}_5\text{NH}_2 + \text{CHCl}_3 + 3\text{KOH} \rightarrow \text{C}_6\text{H}_5\text{NC} + 3\text{KCl} + 3\text{H}_2\text{O} \]
Step 5: Therefore, the reagent ‘X’ is chloroform (CHCl$_3$).