Question

The decreasing order of the rate of nitration of benzene (I), C₆D₆ (II), nitrobenzene (III), chlorobenzene (IV) is ______.

Options

• I > II > III > IV

• I > II > IV > III

• I = II > IV > III

• I = II > III > IV

Answer 1

I = II > IV > III

Explanation:

Rate of nitration is faster when substituent activates the ring (+ l - effect or + R - effect, ortho/para directing) and rate is slower when substituent deactivates the ring (+ l - effect or - R - effect, meta directing group). Halogen deactivates ring but orientation is ortho para directing group.

Rate of \[\ce{C6H6 = C6D6}\], as no effect is observed when H is replaced by D. Hence, order is I = II > IV > III.