JEE PYQ: General Organic Chemistry Question 11
Question 11 - 2021 (25 Feb Shift 2)
The correct order of acid character of the following compounds is:
I: Phenol ($\text{OH}$ on benzene) II: $p$-Nitrobenzoic acid ($\text{COOH}$ with $\text{NO}_2$ group) III: Benzoic acid ($\text{COOH}$) IV: $p$-Methylbenzoic acid ($\text{COOH}$ with $\text{CH}_3$ group)
(1) II > III > IV > I
(2) III > II > I > IV
(3) IV > III > II > I
(4) I > II > III > IV
Show Answer
Answer: (1)
Solution
Acidity of carboxylic acid $\propto$ $-\text{R}$ > $-\text{H}$ > $-\text{I}$. The $\text{NO}_2$ group is electron-withdrawing (−M effect), increasing acidity; $\text{CH}_3$ is electron-donating (+I effect), decreasing acidity. Phenol is the weakest acid. Order: II > III > IV > I.
BETA
