Answer:-

(i) When a primary amine, such as ethylamine, undergoes a reaction with Hinsberg’s reagent (benzenesulfonyl chloride), it forms N-alkyl benzenesulfonamide. This compound is soluble in an aqueous solution of potassium hydroxide (KOH), resulting in the formation of a clear solution of potassium salt. Upon subsequent acidification, the N-alkyl benzenesulfonamide becomes insoluble.