Arrange the following in increasing order of their acidity? (a) $o$ -cresol, (b) salicylic acid, (c) phenol
Arrange the following in increasing order of their acidity?
(a) $o$ -cresol, (b) salicylic acid, (c) phenol
$c < a < b$
$b < c < a$
$a < b < a$
$a < c < b$
Solution
Electron releasing groups etc) intensify the negative charge of phenoxide ion, i.e., destabilizes it hence decreases ionization of parent phenol, therefore decreases acidity. While electron withdrawing groups etc. increases acidity. $\mathrm{CH}_{3}$ is an electron-donating group so its acidity is the least. Salicylic acid has two electron-donating groups so its acidity is the highest.
Therefore, the correct order of increasing order of acidity is:
$a < c < b \mid$