Chemistry - GOC Question with Solution | TestHub

Question Explanation:

Arrange the given two substituted phenols and two substituted carboxylic acids in decreasing order of acidity.

Concept: Acidity of organic compounds depends on the stability of the conjugate base and the effects of substituents: inductive $(-\mathrm{I}/+\mathrm{I})$, resonance $(-\mathrm{M}/+\mathrm{M})$, and comparison of carboxylic acids vs phenols.

Solution:

Carboxylic acids are more acidic than phenols due to greater stabilization of the carboxylate ion by resonance.

Among carboxylic acids: Electron-withdrawing substituents increase acidity, while electron-donating groups decrease it.

Among phenols: –NO₂ (–I, –M) increases acidity more than unsubstituted phenol.

Final Order of Acidity:   III > IV > II > I