Question

Rate determining step in nitration of benzene is

• A. formation of $NO _{2}^{+}$
• B. formation of carbocation
• C. replacement of $H$ atom
• D. none of these

Answer 1

Answer: (B)

formation of carbocation

Answer 2

The nitration of benzene takes places in three steps, i.e. (i) Generation of electrophile $(NO_2^+)$ (ii) Attack of an electrophile to benzene ring forming the carbocation (iii) Loss of proton from carbocation giving nitrobenzene. The attack of electrophile to benzene ring giving a carbocation is the slowest and rate determining step.