Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Order of acidic nature of the following compounds is A>B>C.
Reason R: Fluoro is a stronger electron withdrawing group than Chloro group. In the light of the above statements, choose the correct answer from the options given below:ABC
(A)A is false but R is true
(B)Both A and R are correct and R is the correct explanation of A
(C)Both A and R are correct but R is NOT the correct explanation of A✓ Correct
(D)A is true but R is false
Answer: (C)
Solution
Acidic strength increases with electron-withdrawing groups (−I effect) and decreases with electron-donating groups (+I effect). Compound C has a methyl group (+I), making it the least acidic. Between A (ortho-chloro) and B (para-fluoro), the inductive effect is distance-dependent. The chloro group in the ortho position (A) exerts a stronger −I effect than the fluoro group in the para position (B), making A more acidic than B. Thus, the order A>B>C is correct. While fluorine is indeed a stronger electron-withdrawing group than chlorine (R is true), this does not explain why A is more acidic than B—the position matters more. Therefore, both statements are correct but R is not the correct explanation of A.
JEE Main · 2023 · 13 Apr 2023 · Shift 2 · Single correct option
