Question

Which of the following gives Carbylamine test?

• A. \(R_2NH\)
• B. \(RNH_2\)
• C. \(RNC\)
• D. \(RCN\)

Hint:

Carbylamine test is given only by primary amines, both aliphatic and aromatic. Secondary and tertiary amines do not give this test.

Answer 1

The Correct Option is B

Step 1: Grasping the carbylamine reaction.
The carbylamine test serves to detect primary amines by reacting them with chloroform and alcoholic KOH to generate foul-smelling isocyanides: RNH₂ + CHCl₃ + 3KOH → RNC + 3KCl + 3H₂O.

Step 2: Evaluating the choices.
R₂NH is a secondary amine and does not respond to this test. RNH₂ is a primary amine and gives a positive result. RNC is the product formed, not the reacting amine. RCN is a nitrile and fails the test.

Step 3: Final verdict.
Only primary amines yield a positive carbylamine test, so the answer is RNH₂.