Total number of alkali insoluble solid sulphonamides obtained by reaction of given amines with Hinsberg's reagent is_______.
Aniline, N-Methylaniline, Methanamine, N,N-Dimethylmethanamine, N-Methyl methanamine, Phenylmethanamine, N-propylaniline, N-phenylaniline, N,N-Dimethylaniline, Allyl amine,Isopropyl amine

We need to find the total number of alkali‐insoluble solid sulphonamides formed by the Hinsberg reaction of the given amines.

In the Hinsberg test, primary amines (R-NH₂) react with benzenesulfonyl chloride to form sulphonamides that are soluble in alkali due to acidic N-H and are not counted; secondary amines (R₂NH) react to form sulphonamides that are insoluble in alkali because they lack an acidic N-H and are counted; tertiary amines (R₃N) do not react with Hinsberg's reagent and are not counted.

Classifying the amines, aniline (C₆H₅NH₂), methanamine (CH₃NH₂), phenylmethanamine (C₆H₅CH₂NH₂, benzylamine), allylamine (CH₂=CHCH₂NH₂), and isopropylamine ((CH₃)₂CHNH₂) are primary and form alkali‐soluble sulphonamides, so they are not counted. N,N-Dimethylmethanamine ((CH₃)₃N) and N,N-Dimethylaniline (C₆H₅N(CH₃)₂) are tertiary and do not react, and therefore are not counted. N-Methylaniline (C₆H₅NHCH₃), N-Methylmethanamine ((CH₃)₂NH), N-Propylaniline (C₆H₅NHCH₂CH₂CH₃), and N-Phenylaniline (diphenylamine, (C₆H₅)₂NH) are secondary and each gives an alkali‐insoluble sulphonamide, so they are counted.

The secondary amines N-Methylaniline, N-Methylmethanamine, N-Propylaniline, and N-Phenylaniline each give alkali‐insoluble sulphonamides, adding up to 4.

The answer is Option A: $$4$$.