See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Analysis of Carboxylic Acid Strength **Identify the structures:** - **(I)**: Salicylic acid (ortho-$OH$ on benzene with $COOH$) - **(II)**: Dihydroxybenzoic acid (two $OH$ groups ortho and meta to $COOH$) - **(III)**: Methylbenzoic acid (o-toluic acid, $CH_3$ ortho to $COOH$) - **(IV)**: 4-Hydroxybenzoic acid (para-$OH$ to $COOH$) **Key factors affecting acid strength:** 1. **Electron-withdrawing groups** increase acid strength (stabilize conjugate base) 2. **Electron-donating groups** decrease acid strength (destabilize conjugate base) 3. **Hydrogen bonding effects** can be significant in ortho-substituted compounds **Ranking:** - **II > III > I > IV** ✓ (Option C) **Justification:** - **(II) strongest**: Two $OH$ groups are electron-withdrawing by inductive effect, strongly stabilizing the conjugate base - **(III)**: $CH_3$ is weakly electron-donating (less destabilizing than para-$OH$); ortho position adds some inductive effect - **(I)**: Ortho-$OH$ is electron-donating, but intramolecular H-bonding partially stabilizes the conjugate base (moderate effect) - **(IV) weakest**: Para-$OH$ is strongly electron-donating through resonance, significantly destabilizing the conjugate base **Answer: (C) II > III > I > IV**