Question

Assertion (A): Aromatic primary amines can be prepared by Gabriel Phthalimide synthesis.
Reason (R): Aryl halides do not undergo nucleophilic substitution with the anion formed by phthalimide.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Gabriel Phthalimide synthesis works ONLY for aliphatic primary amines, never for aromatic amines.

Answer 1

The Correct Option is D

Step 1: Gabriel phthalimide synthesis overview.
This method uses the phthalimide anion as a nucleophile in an $S_N2$ attack on an alkyl halide, followed by hydrolysis to give a primary aliphatic amine. It requires a reactive alkyl halide.
Step 2: Evaluate the Assertion.
The Assertion claims that aromatic primary amines CAN be prepared by Gabriel synthesis. This is FALSE. Aniline and other aromatic primary amines cannot be prepared by this route.
Step 3: Why aryl halides are unreactive (Reason).
In aryl halides, the carbon bonded to the halogen is $sp^2$ hybridised and part of the aromatic ring. Resonance delocalises the lone pair of the halogen into the ring, shortening and strengthening the $C-X$ bond and blocking backside $S_N2$ attack. The phthalimide anion cannot displace the halide. Reason (R) is TRUE.
Step 4: Assertion-Reason verdict.
A is false (aromatic amines cannot be made by Gabriel synthesis). R is true (aryl halides do not undergo nucleophilic substitution with the phthalimide anion). This corresponds to option (D).
\[ \boxed{(D)} \]