Chemistry · Aromatic hydrocarbons: Nomenclature, benzene - structure and aromaticity, mechanism of electrophilic substitution, halogenation, nitration
Which of the following steps is not correct in the mechanism of electrophilic su
Which of the following steps is not correct in the mechanism of electrophilic substitution of benzene?
- A. Generation of electrophile like \( X^{+}, R^{+}, R C^{+} O, N O_{2}^{+} \) etc.
- B. Attack of electrophile resulting in the formation of arenium ion in which one of the carbon is \( s p^{3} \) hybridised.
- C. Addition of proton on benzene ring to give carbocation.
- D. Removal of proton from \( s p^{3} \) carbon atom to restore aromatic character.
Step-by-step solution
In the electrophilic substitution mechanism of benzene, the correct steps are: generation of the electrophile (A), attack of the electrophile to form an arenium ion (sigma complex) where one carbon becomes sp³ hybridized (B), and then removal of a proton from that sp³ carbon to restore aromaticity (D). Step C incorrectly describes addition of a proton to benzene, which does not occur; instead, the electrophile adds. Thus, C is not correct.