question_answer

Arrange the following in increasing order of their acidity? [a] o-cresol, [b] salicyclic 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 decrease ionization of parent phenol. Therefore decreases acidity while electron donating groups \[(-N{{O}_{2}},-COOH,-CHO\,etc.)\]  increases acidity.