Assertion (A): Gabriel phthalimide synthesis can be used to prepare both aromatic and aliphatic primary amines.
Reason (R): Aryl halides undergo nucleophilic substitution with the anion formed by phthalimide as readily as alkyl halides do.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Both (A) and (R) are false.
In Gabriel phthalimide synthesis the potassium salt of phthalimide is heated with a halide, and the phthalimide anion replaces the halogen by nucleophilic substitution; alkaline hydrolysis then sets the primary amine free:
\( \displaystyle \ce{C6H4(CO)2N^-K^+ + R-X} \xrightarrow{\Delta} \ce{C6H4(CO)2N-R + KX} \)
Assertion (A): Gabriel phthalimide synthesis can be used to prepare both aromatic and aliphatic primary amines. — False. The method gives only aliphatic primary amines (from alkyl halides). Aromatic primary amines such as aniline cannot be prepared by it.
Reason (R): Aryl halides undergo nucleophilic substitution with the anion formed by phthalimide as readily as alkyl halides do. — False. Aryl halides do not undergo nucleophilic substitution with the phthalimide anion, so the first step above fails when R–X is an aryl halide.
NCERT (2026-27 edition):
9.4 Preparation of Amines – “Gabriel synthesis is used for the preparation of primary amines. … Aromatic primary amines cannot be prepared by this method because aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.”