Question

What is the maximum number of compounds with the molecular formula $C_4{H}_{11}N$, which give an
alkali soluble precipitate with benzenesulphonyl chloride?

Answer 1

Only primary amines upon reaction with Hinsberg's reagent produce alkali soluble precipitate. Since degree of unsaturation is zero so unsaturation is absent. There are 5 isomers having primary amine as functional group (including stereoisomers) possible for $C_4{H}_{11}N$.