Benzenesulphonyl chloride(C6H5SO2Cl)is also known as Hinsberg's reagent. It reacts with the primary and secondary amine to form sulphonamides. Secondary and tertiary amines can be distinguished by allowing them to react with Hinsberg's reagent ( benzene sulphonyl chloride C6H5SO2Cl). Secondary amines react with Hinsberg's reagent to form a product that is insoluble in an alkali. For example, N,N - diethylamine reacts with Hinsberg's reagent to form N,N− diethyl benzene sulphonamide, which is insoluble in an alkali. Tertiary amines, however, do not react with Hinsberg's reagent.