Question

Which one of the following compounds will be most readily
attacked by an electrophile ?
(a) Chlorobenzene (b) Benzene
(c) Phenol (d) Toluene

Answer 1

Which one of the following compounds will be most readily

attacked by an electrophile ?

(a) Chlorobenzene

(b) Benzene

(c) Phenol

(d) Toluene

Answer 2

Compound which would be most readily attacked by an electrophile is :

a) Chlorobenzene ( C₆H₅Cl )

• Presence of deactivating group like chlorine, decrease electron density on benzene making it less favorable for electrophilic substitution.

b) Benzene ( C₆H₆ )

• It favor electrophilic substitution, as it is electron rich and attracts electrophile.

c) Phenol ( C₆H₅OH )

• Donation of the oxygen's lone pair into the ring system increases the electron density around the ring ( +M effect ). And increases rate for electrophilic substitution.

d) Toluene ( C₆H₅CH₃ )

• The CH₃ group attached to the benzene ring increases the electron density through ( + H and +I effect ).

• Resonance effects are generally far more superior as compared to hyperconjugation.

• Hence phenol would be most readily attacked by an electrophile.