Question

The order of decreasing reactivity towards an electrophilic reagent, for the following would be

(i) benzene 

(ii) toluene

(iii) chlorobenzene 

(iv) phenol

(a) (ii) > (iv) > (i) > (iii) 

(b) (iv) > (iii) > (ii) > (i)

(c) (iv) > (ii) > (i) >( iii) 

(d) (i) > (ii) > (iii) > (iv)

Answer 1

The correct option is: (c) (iv) > (ii) > (i) >( iii)

Explanation:

Electrophiles are electron loving chemical species. They attack at the highest electron density site of the substrate. Electron donating substances (+I effect) increases the electron density of the molecule. +I effect decreases in the order:

-OH > - CH₃ > - H > - Cl

Hence order of decreasing reactivity towards electrophile is

C₆H₅OH > C₆H₅CH₃ > C₆H₆ > C₆H₅Cl.