Question

Which of the following compound(s) will not dissolve in an alkali solution after it has undergone reaction with Hinsberg's reagent?

• A. Diethyl amine
• B. Isopropyl amine
• C. N-methyl ehtanamine
• D. N,N-dimethyl aniline

Answer 1

The correct option is C N-methyl ehtanamine

Hinsberg reagent is Benzenesulphonyl chloride $\left(C_6{H}_{5}S{O}_{2}Cl\right)$. It reacts with primary and secondary amines to form sulphonamides.

It reacts with primary amine to form acidic compound which is soluble in alkali because hydrogen (H) attached to nitrogen(N) in sulphonamide is strongly acidic due to presence of stronf electron withdrawing sulphonyl group.

Now, out of the options given in the question, only isopropyl amine is a primary amine. Dimethyl amine and N-methyl ethaneamine are secondary amines and N,N-dimethylaniline is tertiary amine.

Hence,option (b) is correct.