Which of the two reactions proceed faster ?

Options

A. `(i)`
B. `(ii)`
C. `(i)=(ii)`
D. `Not definite

Answer

C

Explanation

Electrophiilic substitution in benzene is a two`-` step reaction in which slow step `(` first step `)` is common in both reactions and it does not involve the breaking of `C-H` or `C-D` bond.

Had the rate determining step `(` slow step `)` involved the cleavage of `C-H` or `C-D` bond, nitration of benzene would have been fasterthan that of hexadeuterated benzene.