NEET Chemistry: Kinetics questions with solutions

Q1. Assertion Rate of nitration is \( C_{6} H_{6} \simeq C_{6} D_{6} \simeq \) \( \boldsymbol{C}_{\boldsymbol{6}} \boldsymbol{T}_{\boldsymbol{6}} \) Reason Formation of intermediate is rate determining step in nitration of benzene, not the breaking of \( \boldsymbol{C}-\boldsymbol{H} \) or \( C-D \) bond

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Answer: Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

In nitration of benzene, the slow step is formation of the sigma complex (arenium ion), not cleavage of the aromatic C–H bond. Since the rate-determining step does not involve breaking C–H, C–D, or C–T bonds, the rates for C6H6, C6D6, and C6T6 are nearly the same.