Statement I: It is difficult to replace chlorine by –OH in chlorobenzene in comparison to that in chloroethane
Statement II: Chlorine – carbon (C–Cl) bond in chlorobenzene have double bond character due to resonance.
Answer & explanation
Correct answer: option 1
The answer is (1) both statement I and statement II are correct and statement II is the correct explanation of statement I.
Statement I is correct because the chlorine-carbon bond in chlorobenzene has a partial double bond character due to resonance. This makes the chlorine atom less electronegative and less likely to be replaced by a nucleophile.
Statement II is also correct because the partial double bond character in the chlorine-carbon bond is caused by resonance. This means that statement II provides the reason for the decreased reactivity.
Here is a diagram that shows the resonance structures of chlorobenzene:
As you can see, the chlorine atom is sharing a pair of electrons with the benzene ring, giving the bond a partial double bond character. This makes the chlorine atom less electronegative and less likely to be replaced by a nucleophile.
Therefore, both statement I and statement II are correct and statement II is the correct explanation of statement I.