Question

When aniline is heated with CHCl₃ in the presence of KOH, the product formed is

• A. Phenyl isothiocyanate
• B. Phenyl isocyanide
• C. Phenyl cyanide
• D. Phenol

Hint:

Primary amine + CHCl₃ + alcoholic KOH is the carbylamine reaction, giving a foul-smelling isocyanide.

Answer 1

The Correct Option is B

Step 1: Identify the diagnostic test being described. Chloroform plus a strong base with a primary amine is the classic carbylamine reaction, used to detect primary amines by their offensive odour.
Step 2: KOH and CHCl₃ generate the reactive intermediate dichlorocarbene (:CCl₂), which inserts into the N-H of the primary amine. After loss of HCl the nitrogen becomes bonded to carbon through the isocyanide linkage.
Step 3: Applying this to aniline gives phenyl isocyanide, C₆H₅-N=C. The overall equation is C₆H₅NH₂ + CHCl₃ + 3KOH → C₆H₅NC + 3KCl + 3H₂O.
Result: The product is phenyl isocyanide, alternative (ii).