Question

Carbylamine test is performed in alcoholic $KOH$ by heating a mixture of:

• A. chloroform and silver powder
• B. trichloromethane and a primary amine
• C. an alkyl halide and a primary amine
• D. an alkyl cyanide and a primary amine

Answer 1

The correct option is B trichloromethane and a primary amine

Carbylamine reaction mechanism includes the addition of amine to the intermediate created from the dehydrohalogenation of chloroform. This intermediate is called dichlorocarbene. The carbylamine reaction is also known as Hoffmann isocyanide synthesis. It is the reaction of a primary amine, chloroform and a base to synthesize isocyanides. The dichlorocarbene intermediate is very important for this conversion. The carbylamine reaction cannot be used to synthesize isocyanides from secondary or tertiary amines.
$RN{H}_2+CHC{l}_3+KOH\to \stackrel{\oplus }{RN}\equiv \stackrel{\ominus }{C}+3H_{2}O+3KCl$

It gives an offensive smell because of isocyanide.

Hence, option (b) is correct.