Question

The conversion of X to Y is:

• A. Hoffmann reaction
• B. Etard reaction
• C. Stephen reaction
• D. Carbylamine reaction

Hint:

The Carbylamine reaction is a test for primary amines, producing foul-smelling isocyanides when treated with CHCl$_3$ and alcoholic KOH.

Answer 1

The Correct Option is D

Step 1: Conversion of Benzamide to X
The first step involves the reaction of benzamide (\(\text{C}_6\text{H}_5\text{CONH}_2\)) with bromine in sodium hydroxide (Br}_2/\text{NaOH}), which leads to the formation of aniline (\(\text{C}_6\text{H}_5\text{NH}_2\)) via the Hoffmann bromamide degradation reaction: \[ \text{C}_6\text{H}_5\text{CONH}_2 + \text{Br}_2 + 4\text{NaOH} \rightarrow \text{C}_6\text{H}_5\text{NH}_2 + \text{Na}_2\text{CO}_3 + 2\text{NaBr} + 2\text{H}_2\text{O} \] Step 2: Conversion of X to Y (Carbylamine Reaction)
The second step involves the reaction of aniline (\(\text{C}_6\text{H}_5\text{NH}_2\)) with chloroform (CHCl}_3) and alcoholic potassium hydroxide (\(\text{alc. KOH}\)). This reaction is called the Carbylamine reaction, and it produces phenyl isocyanide (\(\text{C}_6\text{H}_5\text{NC}\)) with a foul odor: \[ \text{C}_6\text{H}_5\text{NH}_2 + \text{CHCl}_3 + 3\text{KOH} \rightarrow \text{C}_6\text{H}_5\text{NC} + 3\text{KCl} + 3\text{H}_2\text{O} \] Step 3: Analysis of the Given Options 
- Hoffmann Reaction: - This reaction converts amide to amine using $Br_2\text{NaOH}$, which forms aniline (X). However, the complete transformation to phenyl isocyanide (Y) is not due to Hoffmann degradation. 
- Etard Reaction: - The Etard reaction is used to oxidize toluene to benzaldehyde, which is unrelated to this transformation. 
- Stephen Reaction: - This reaction reduces nitriles to aldehydes in the presence of $SnCl_2HCl$, which is also unrelated here. 
- Carbylamine Reaction: - This is the correct reaction responsible for converting aniline to phenyl isocyanide, which matches the given conversion. 
Final Answer: 
The correct answer is (4) Carbylamine reaction, as it correctly explains the transformation of aniline (\(X\)) to phenyl isocyanide (\(Y\)).