See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Acid Strength **Key Principle:** Acid strength depends on the stability of the conjugate base. More stable conjugate bases → stronger acids. ## Evaluating Each Compound: **(A) Aspirin:** - Has $COOH$ (carboxylic acid) directly attached to benzene ring - Conjugate base: $COO^-$ stabilized by benzene ring resonance - Moderate acid strength **(B) Oil of wintergreen (methyl salicylate):** - Has both $COOH$ AND an adjacent $-O-C(=O)-CH_3$ (ester group) - The ester is **electron-withdrawing** via inductive effect - This electron withdrawal **destabilizes the $OH$ bond**, making H⁺ easier to remove - Conjugate base $COO^-$ is further stabilized by electron-deficient ring - **Strongest acid** among the options **(C) o-Methoxycarbonyl benzoic acid:** - Has $COOH$ and $-C(=O)-OCH_3$ (ester) - Similar to (B), but ester group is **one position away** (less direct inductive effect) - Weaker than (B) **(D) o-Toluic acid:** - Has only $COOH$ and a methyl group ($-CH_3$) - Methyl is **electron-donating** (weakly) - Destabilizes conjugate base slightly - **Weakest acid** ## Answer: **(B)** The ortho-ester group in compound (B) directly withdraws electron density through the inductive effect, making the carboxylic acid more acidic than the others.