question_answer

Arrange the following in increasing order of their acidity? [a] o-cresol, [b] salicylic acid, [c] phenol

A) \[c<a<b\]         

B) \[b<c<a\]

C) \[a<b<a\]        

D) \[a<c<b\]

Correct Answer: D

Solution :

[d] Electron releasing groups \[(-C{{H}_{3}},-OC{{H}_{3}},-NC{{H}_{3}}etc)\] intensify the negative charge of phenoxide ion, i.e., destablises it hence decreases ionization of parent phenol, therefore decreases acidity. While electron withdrawing groups \[\left( -N{{O}_{2}}\text{,}-COOH,-CHO\text{ }etc. \right)\] increases acidity.