Question

Why do we get isopropyl benzene on treating benzene with 1-chloropropane instead of n- propyl benzene ?

Answer 1

When benzene reacts with 1-chloropropane in presence of $AlC{l}_3$, the formation of primary carbocation takes place.

The primary carbocation is less stable than secondary carbocation.

So this primary carbocation undergoes rearrangement reaction to form a secondary carbocation.

Because of this rearrangement, we get isopropyl benzene instead of n-propylbenzene.