JEE Advanced2009ChemistryCarboxylic Acid DerivativesActual
The correct acidity order of the following is
Options
- AIII > IV > II > I
- BIV > III > I > II
- CIII > II > I > IV
- DII > III > IV > I
Correct answer
A. III > IV > II > I
Step-by-step solution
A carboxylic acid is stronger acid than phenol, hence both III and IV are stronger acids than both I and II. Also IV has a methyl group that gives electron donating inductive effect and decreases the acid strength. Therefore, III is stronger acid that IV. Between I and II, the dominant electron withdrawing inductive effect of chlorine increases acid strength of phenol slightly, hence II is stronger acid than I. Thus, the overall order is : (a) III > IV > II > I