Answer the question on the basis of passage given below:

There are three kinds of amines which are primary, secondary and tertiary amines. These amines may have alkyl group or aryl group or both alkyl and aryl groups. These amines can be distinguished from one another by various chemical tests.

An amine \(A\) on treatment with benzene sulphonyl chloride gives a compound \(B\) which easily dissolves in an alkali; the \(A\) is :

Primary amine

The correct answer is option 1. Primary amine.

The reaction described in the question is a classic test for identifying the type of amine (primary, secondary, or tertiary) known as the Hinsberg test. Benzene sulphonyl chloride \(C_6H_5SO_2Cl\) is the reagent used in this test.

Reaction and Solubility:

Primary Amines: When a primary amine (A) reacts with benzene sulphonyl chloride, it forms a primary sulphonamide (B). Primary sulphonamides are soluble in alkali (aqueous solution of \(NaOH\) or \(KOH\)).

Secondary Amines: Secondary amines react with benzene sulphonyl chloride to form secondary sulphonamides. However, these secondary sulphonamides are insoluble in alkali.

Tertiary Amines: Tertiary amines do not react with benzene sulphonyl chloride under these conditions.

Explanation:

The fact that the resulting compound (B) easily dissolves in alkali indicates that the starting amine (A) must be a primary amine. Primary amines can form an acidic \(N-H\) bond with the sulphonyl group \(C_6H_5SO_2^-\), making the resulting primary sulphonamide soluble in the basic solution (alkali).

Secondary and tertiary amines lack this reactive \(N-H\) bond, leading to products insoluble in alkali.

Therefore, based on the solubility behavior of the product in alkali, the starting amine (A) must be a primary amine.