What is the major product of the reaction of ${\text{C}}_6{\text{H}}_6$ with ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{Cl}$ in the presence of ${\text{AlCl}}_3$?

Solution

1. The reaction of ${\text{CH}}_3{\text{CH}}_2{\text{CH}}_2\text{Cl}$ with ${\text{AlCl}}_3$ generates a primary propyl carbocation.
2. The primary carbocation undergoes a 1,2-hydride shift to form a more stable secondary isopropyl carbocation.
3. The secondary carbocation attacks the benzene ring.
4. The final product is isopropylbenzene.
5. Hence the answer is (B).