Question

Assertion (A): Carbon halogen bond in aryl and vinyl halides are unusually shorter. Reason (R): Chlorobenzene and vinyl chlorides undergo $S_N1$ and $S_N2$ reaction in general.

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Resonance = Double bond character = Shorter bond = Harder to break (low reactivity).

Answer 1

The Correct Option is C

Step 1: Concept In aryl and vinyl halides, the halogen's lone pair is in resonance with the $\pi$ system, giving the C-X bond partial double-bond character.

Step 2: Meaning Partial double-bond character and $sp^2$ hybridization of the carbon lead to a shorter, stronger bond.

Step 3: Analysis Assertion (A) is correct. However, Reason (R) is false; aryl and vinyl halides are generally inert to $S_N1$ and $S_N2$ reactions due to this partial double bond and the instability of the resulting cations.

Step 4: Conclusion Statement (A) is correct, but statement (R) is incorrect. Final Answer: (3)