Question

Isomeric amines with molecular formula C₈ H₁₁N give the following tests
Isomer (P) ⇒ Can be prepared by Gabriel phthalimide synthesis
Isomer (Q) ⇒ Reacts with Hinsberg’s reagent to give solid insoluble in NaOH
Isomer (R) ⇒ Reacts with HONO followed by β-naphthol in NaOH to give red dye.
Isomers (P), (Q) and (R) respectively are

• A.
• B.
• C.
• D.

Hint:

The Gabriel phthalimide synthesis is specific to primary amines. Hinsberg’s reagent helps distinguish between primary, secondary, and tertiary amines based on solubility behavior. The reaction with HONO and β-naphthol confirms the presence of an aromatic primary amine.

Answer 1

The Correct Option is D

Step 1: Analyzing Isomer (P) 

Gabriel phthalimide synthesis is specifically used to prepare primary amines. Therefore:

(P) must be a primary amine.

Step 2: Analyzing Isomer (Q)

Hinsberg’s reagent reacts with secondary amines to form a solid product that is insoluble in NaOH. Therefore:

(Q) must be a secondary amine.

Step 3: Analyzing Isomer (R)

Reaction with HONO followed by β-naphthol in NaOH produces a red dye, which is a characteristic test for aromatic primary amines. Therefore:

(R) must be an aromatic primary amine.

Conclusion:

Final Answer: (4)