Primary amine on treatment with benzenesulphonyl chloride forms a product which is soluble in…………..

Question 19:Primary amine on treatment with benzenesulphonyl chloride forms a product which is soluble in NaOH however secondary amine gives product
which is insoluble in NaOH.

The correct answer is – When a primary amine is treated with benzenesulfonyl chloride (BSCl), the amine group (-NH2) reacts with the BSCl to form a sulfonamide functional group (-NH-SO2Ph) with the release of HCl. The resulting product is a water-soluble sulfonamide that can be deprotonated by a strong base like NaOH to form the corresponding water-soluble sulfonamide salt. This is because the sulfonamide functional group is polar and can form hydrogen bonds with water and Na+ ions. On the other hand, when a secondary amine is treated with BSCl, the reaction also forms a sulfonamide functional group (-NHR-SO2Ph) but the resulting product is insoluble in NaOH. This is because the sulfonamide functional group is no longer able to form a salt with NaOH due to the presence of the alkyl group (R) attached to the nitrogen atom. The alkyl group is nonpolar and cannot form hydrogen bonds with water and Na+ ions, making the resulting sulfonamide insoluble in NaOH. Therefore, the solubility of the product of the reaction between a primary or secondary amine with BSCl in NaOH depends on the presence or absence of an alkyl group attached to the nitrogen atom in the sulfonamide functional group. Primary amines give water-soluble sulfonamides, while secondary amines give water-insoluble sulfonamides.