Question

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

• A. (i) < (ii) < (iii)
• B. (ii) < (i) < (iii)
• C. (iii) < (iii) < (i)
• D. (iii) < (ii) < (i)

Answer 1

Answer: (C)

(iii) < (iii) < (i)

Answer 2

The order of stability of benzyl carbocations is:

$\stackrel { + } { \mathrm { C } } \mathrm { H } _ { 2 } > \mathrm { Cl }$

The electron withdrawing effect of $- \mathrm { NO } _ { 2 }$ group is greater than that of group.

Thus, the correct increasing order of reactivity with HBr/HCl is : (ii) < (iii) < (i).