What happens when benzene reacts with n-propylchloride in presence of anhydrous aluminium chloride ? 

Explanation

The major product of the reaction is isopropyl benzene called as cumene.

The initially formed `CH_3 CH_2overset(+)(C)H_2` gets rearranged to more stable secondary carbocation `CH_3 overset(+)(C)HCH_3`
 Hence the major product is isopropyl benzene and minor product is propyl benzene.
`CH_3CH_2CH_2CI+AICI_3 `CH_3CH_2 overset(+)(C)H_2 overset(H^(-)" shift")(rarr)CH_3overset(+)(C)HCH_3`