On heating an aliphatic primary amine with chloroform and ethanolic potassium hydroxide, the organic compound formed is 

On heating an aliphatic or aromatic primary amine with chloroform and ethanolic potassium hydroxide, the organic compound formed is a foul smelling alkyl isocyanide.

$\mathrm{R}-\stackrel{ }{{\mathrm{NH}}_2}+{\mathrm{CHCl}}_3 + 3\mathrm{KOH} \underset{∆}{\overset{{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{OH}/\mathrm{KOH}}{\to }} \underset{\mathrm{alkyl} \mathrm{isocyanide}}{\mathrm{R}-\mathrm{NC}} + 3\mathrm{KCl} + 3{\mathrm{H}}_2\mathrm{O}$

This reaction is known as Hoffmann's carbylamines reaction or isocyanide test and is used as a test for primary amines. This test is not given by secondary and tertiary amines.