Although chlorine is an electron withdrawing group, yet it is ortho- and para-directing in electrophilic aromatic substitution reaction because
(A) Chlorine withdraws electrons through inductive effect.
(B) Chlorine destabilises the intermediate carbocation formed during electrophilic substitution.
(C) Chlorine accepts electrons through resonance.
(D) Chlorine releases electrons through resonance.
Choose the correct answer from the options given below :
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (A), (B) and (D) only
Chlorine affects the benzene ring in two opposite ways. By its −I (inductive) effect it withdraws electrons from the ring and destabilises the carbocation formed during electrophilic substitution; this is why chlorobenzene reacts more slowly than benzene. By its +R (resonance) effect, a lone pair of chlorine is released into the ring, which increases the electron density at the ortho and para positions and stabilises the carbocations formed by attack there. The inductive effect is the stronger one and decides the rate; the resonance effect decides where the electrophile goes.
(A) Chlorine withdraws electrons through inductive effect. — Correct. It is more electronegative than carbon.
(B) Chlorine destabilises the intermediate carbocation formed during electrophilic substitution. — Correct. Through its inductive effect it does so, which makes chlorobenzene less reactive than benzene.
(C) Chlorine accepts electrons through resonance. — Incorrect. Chlorine donates a lone pair to the ring by resonance; it does not accept electrons.
(D) Chlorine releases electrons through resonance. — Correct. This raises the electron density at the ortho and para positions and makes chlorine ortho and para directing.
NCERT (2026-27 edition):
Reactions of Haloarenes – “… Chlorine withdraws electrons through inductive effect and releases electrons through resonance. Through inductive effect, chlorine destabilises the intermediate carbocation formed during the electrophilic substitution. Through resonance, halogen tends to stabilise the carbocation and the effect is more pronounced at ortho- and para- positions. The inductive effect is stronger than resonance and causes net electron withdrawal and thus causes net deactivation. The resonance effect tends to oppose the inductive effect for the attack at ortho- and para- positions and hence makes the deactivation less for ortho- and para- attack. Reactivity is thus controlled by the stronger inductive effect and orientation is controlled by resonance effect.”