A student adds benzenesulphonyl chloride to excess aqueous KOH and then the amine. For which amines does the mixture give a clear alkaline solution (soluble sulphonamide salt)? (more than one may be correct)

A $(CH X_{3} CH X_{2}) X_{3} N$
B $CH X_{3} CH X_{2} NH X_{2}$
C $C X_{6} H X_{5} NH X_{2}$
D $(CH X_{3} CH X_{2}) X_{2} NH$

Answer: B, C

In the Hinsberg test a primary amine gives

RNHSO X_{2} C X_{6} H X_{5}

, whose N-H is acidic and dissolves in KOH as the sodium salt. A secondary amine gives an insoluble sulphonamide and a tertiary amine does not react. Ethylamine and aniline are primary.

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A student adds benzenesulphonyl chloride to excess aqueous KOH and then the amine. For which amines does the mixture give a clear alkaline solution (soluble sulphonamide salt)? (more than one may be correct)

Answer: B, C

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