MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

Acidic strength of phenols is directly proportional to the stability of the phenoxide ion formed after losing a proton. Electron-withdrawing groups stabilize the phenoxide ion through -I and -R effects, thereby increasing the acidic strength. Electron-donating groups destabilize the phenoxide ion through +I, +H, and +R effects, thereby decreasing the acidic strength. In p-nitrophenol (III), the -NO_2 group exerts strong -R and -I effects, making it the most acidic. In p-chlorophenol (I), the -Cl group exerts a -I effect which dominates over its +R effect, making it more acidic than phenol but less acidic than p-nitrophenol. In p-cresol (II), the -CH_3 group exerts +I and hyperconjugation (+H) effects, decreasing the acidic strength compared to phenol. In p-methoxyphenol (IV), the -OCH_3 group exerts a strong +R effect which dominates over its -I effect, making it the least acidic. Thus, the decreasing order of acidic strength is III > I > II > IV. Answer: III > I > II > IV