Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). In the light of the above statements, choose the most appropriate answer from the options given below :
- (A) is not correct but (R) is correct
- Both (A) and (R) are correct and (R) is the correct explanation of (A)
- Both (A) and (R) are correct but (R) is not the correct explanation of (A)
- (A) is correct but (R) is not correct
Answer
(4) (A) is correct but (R) is not correct
Solution
As per NCERT, chlorine withdraws electrons through inductive effect and releases electrons through resonance.
Through resonance, electron density increases more at the ortho and para positions, so the halogen is ortho, para directing and Assertion (A) is correct.
Through inductive effect chlorine destabilises the intermediate carbocation, while through resonance the halogen tends to stabilise it, and this effect is more pronounced at the ortho and para positions.
∵ The inductive effect is stronger than the resonance effect and causes net electron withdrawal (deactivation of the ring), the resonance effect is not the more pronounced one.
∴ The statement in Reason (R), that the resonance effect is more pronounced (than the inductive effect), is not correct.
Answer: (4)