Give a brief description of the ordinary distillation (simple distillation). 

Simple distillation: The process of converting an organic liquid to its vapours and then condensing the vapours to its pure form in the liquid state is called distillation. This technique is applied:
(i) to purify a liquid containing a non-volatile miscible impurity say benzene and benzophenone.
(ii) for the separation of two liquids having boiling point difference more than about 313 K.
The impure liquid is taken in a distillating flask and apparatus is arranged as shown. The liquid is heated, when it vapourises. These vapours are condensed and the pure liquid is collected in the receiver. The impurities remain in the flask.