Identify A and B in the following reactions. C 6 H 5 CH 2 Br → KCN alco . A → Na / ethanol B

C 6 H 5 CH 2 Br → [ KCN ] [ alco . ] C 6 H 5 - CH 2 - C ≡ N → [ Na / ethanol ] C 6 H 5 - CH 2 - CH 2 - NH 2 Benzyl bromide Phenylacetonitrile 2 - Phenylethylamine Benzyl bromide on reaction with alcoholic potassium cyanide will give benzyl cyanide. Here the potassium will have positive charge and cyanide will have negative charge here the negative charge of cyanide attacks on benzyl bromide and will break the bond. Then benzyl cyanide on reduction give 2 -Phenylethylamine.

Explain carbylamine reaction with an example.

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 Hofmann 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. In general, the carbylamine reaction can be written as follows, R - NH 2 + CHCl 3 + 3 KOH → RNC ( Carbylamine ) + 3 KCl + 3 H 2 O .