Question

Mark the correct increasing order of reactivity of the following compounds with $HBr/HCl$ :

• A. I < II < III
• B. II < I < III
• C. II < III < I
• D. III < II < I

Answer 1

Answer: (C)

Electron withdrawing groups, i.e. $- NO _{2},- Cl$ etc. decreases the stability of carbocation. Since, the $- NO _{2}$ group is a stronger electron withdrawing group than -Cl, therefore, the stability of benzyl carbocations increases in the order:



Hence, the reactivity of benzyl alcohol increases in the same order, i.e., II < III < I