Question

Which of the following reactions is given by only primary amines?

• A. Reaction with HNO2
• B. Reaction with chloroform and alcoholic KOH
• C. Reaction with acetyl chloride
• D. Reaction with Grignard reagent

Hint:

Primary amines react with chloroform and alcoholic KOH to form an isocyanate.

Answer 1

The Correct Option is B

Step 1: Understanding the reactivity of primary amines.
Primary amines undergo a unique reaction with chloroform and alcoholic KOH, known as the Hofmann degradation reaction, which results in the formation of a primary amine.

Step 2: Explanation of the options.
- (1) Reaction with HNO2: Both primary and secondary amines can react with nitrous acid (HNO2), producing diazonium salts.
- (2) Reaction with chloroform and alcoholic KOH: This reaction is specific to primary amines, where they react to form an isocyanate, followed by further degradation.
- (3) Reaction with acetyl chloride: Acetyl chloride reacts with both primary and secondary amines, forming amides.
- (4) Reaction with Grignard reagent: This reaction generally involves alkyl or aryl Grignard reagents and reacts with carbonyl compounds, but is not specific to primary amines.

Step 3: Conclusion.
The correct answer is (2) Reaction with chloroform and alcoholic KOH.