Question

Consider the following phenols as shown in the figure. The decreasing order of acidity of the above phenols is: 

• A. III > IV > II > I
• B. II > I > IV > III
• C. I > IV > II > III
• D. III > IV > I > II

Hint:

Electron-withdrawing groups increase acidity, while electron-donating groups decrease acidity.

Answer 1

The Correct Option is A

Step 1: Nitro group (\(-\mathrm{NO_2}\)) is a strong electron-withdrawing group and increases acidity.
Step 2: In aqueous medium, p-nitrophenol is more acidic than o-nitrophenol due to intramolecular hydrogen bonding in o-nitrophenol, which reduces ionization.
Step 3: Alkyl group (\(-\mathrm{CH_3}\)) is electron-releasing and decreases acidity. \[ \text{p-Nitrophenol} > \text{o-Nitrophenol} > \text{Phenol} > \text{Cresol} \]