When reacts with alcoholic `KCN`, a mixture of isomeric products is obtained. Explain.

Explanation

The nuleophilic substitution (`S_(N)`) reaction can proceed b y both `S_(N^(2))` and `S_(N^(1))` mechanism.
`S_(N^(2))` mechanism: in the case, only one product is formed since the nucleophilc `CN^(-)` ion displaces `Cl^(-)` ion without forming any intermdiate.

`S_(N^(1))` mechanism: in this case, a carbocation intermediate is initially formed in a slow step which rearranges to a more stable carbocation. As a result, a mixture of two isomeric products if formed.