See image — GOC and Organic Chemistry Basics Chemistry Question

💡 Solution & Explanation

# Order of Acidic Strength Analysis **Key Principle:** Acidity of phenols is enhanced by **electron-withdrawing groups** (EWG) and weakened by **electron-donating groups** (EDG). ## Analysis of Each Compound: **(A) p-Cresol (4-methylphenol):** - $CH_3$ is an EDG (electron-donating via +I effect) - Destabilizes the phenoxide ion by increasing electron density - **Weakest acid** **(B) Phenol:** - No substituent; baseline acidity - Moderate strength **(C) p-Nitrophenol:** - $NO_2$ is a strong EWG (electron-withdrawing via -I and -R effects) - In para position: directly stabilizes the negative charge of phenoxide - **Very strong acid** **(D) m-Nitrophenol:** - $NO_2$ is an EWG, but in meta position - Less effective stabilization of phenoxide than para - **Strong acid, but weaker than (C)** ## Order: $C > D > B > A$ **Explanation:** The ortho/para effects of electron-withdrawing $NO_2$ make **C (p-nitrophenol) most acidic**, followed by meta-substituted D. Unsubstituted phenol B is intermediate, while the electron-donating methyl group makes A the weakest. **Answer: Option (1) - $C > D > B > A$ ✓**