Rectified spirit obtained by fermentation contains 5% of water. In order to remove water rectified spirit is mixed with suitable quantity of benzene and heated. This is due to

it is a dehydrating agent and removes water

it forms the lower layer which retains all the water so that alcohol can be distilled off

it forms and azetropic mixture having boiling point and thus allows the alcohol to distill over

It forms low boiling azeotropic mixture which distills over, leaving behind pure alcohol which can then be distilled.