Question

Which among the following react with Hinsberg's reagent?

Choose the correct answer from the options given below:

• A. B and D only
• B. C and D only
• C. A, B and E only
• D. A, C and E only

Hint:

Hinsberg's reagent is a useful test for distinguishing primary and secondary amines from tertiary amines, as tertiary amines do not react due to the absence of a replaceable hydrogen atom on nitrogen.

Answer 1

The Correct Option is D

Hinsberg's reagent is benzenesulfonyl chloride ($C_6H_5SO_2Cl$). It's used to distinguish between primary, secondary, and tertiary amines.

1. Reaction with Different Amines:

• Primary amines react with Hinsberg's reagent to form an N-alkyl or N-aryl benzenesulfonamide. The product is soluble in alkali due to the presence of acidic hydrogen.
• Secondary amines react to form N,N-dialkyl or N,N-diaryl benzenesulfonamides. The product is insoluble in alkali because it has no acidic hydrogen.
• Tertiary amines do not react with Hinsberg's reagent because they do not have a replaceable hydrogen atom on the nitrogen.

2. Analyzing the Given Options:

• (A) Aniline ($C_6H_5NH_2$) is a primary amine.
• (2) N,N-Dimethylaniline ($C_6H_5N(CH_3)_2$) is a tertiary amine.
• (C) Methylamine ($CH_3NH_2$) is a primary amine.
• (4) Trimethylamine ($N(CH_3)_3$) is a tertiary amine.
• (E) Diphenylamine ($(C_6H_5)_2NH$) is a secondary amine.

3. Conclusion:
Therefore, options A, C, and E will react with Hinsberg's reagent.

Final Answer:
The final answer is $A, C, E$.