JEE Chemistry 2023 Question with Solution

Given: The compound has molecular formula $C_4H_{11}N$, shows optical activity, gives $N_2$ with $HNO_2$, and with Hinsberg reagent $PhSO_2Cl$ forms a product soluble in KOH.

Find: The correct structure of A.

Amines that react with $HNO_2$ to evolve $N_2$ are primary aliphatic amines. Also, formation of a sulfonamide soluble in KOH with Hinsberg reagent confirms that the amine is primary.

Among the given structures, the compound must therefore be a primary amine and must also show optical activity. A straight-chain primary amine is not optically active, but the branched primary amine in option D has a chiral carbon atom.

Therefore, the correct option is D.

Given:

• $C_4H_{11}N$
• Reaction with $HNO_2$ gives $N_2$
• Reaction with $PhSO_2Cl$ gives a product soluble in KOH
• The compound shows optical activity

Find: Which option satisfies all conditions.

From the reaction with $HNO_2$:

This identifies A as a primary aliphatic amine.

From the Hinsberg test, a primary amine forms a sulfonamide containing an acidic hydrogen, so it dissolves in KOH. Hence the structure must again be a primary amine.

Now apply the condition of optical activity. The compound must contain a chiral carbon attached to four different groups. Among the given options, only option D satisfies both the primary amine test and chirality requirement.

Therefore, the structure of A is option D.