Question

Arrange the following in increasing acidic character
Phenol, m - nitrophenol, m - chlorophenol, m - cresol
I II III IV

• A. IV < I < III < II
• B. IV < I < II < III
• C. I < IV < III < II
• D. III < II < IV < I

Answer 1

The correct option is A

IV < I < III < II

Here the substituents are present in m - position, so they will not show any mesomeric effect; only inductive effect operates, $-N{O}_2$ group has + cahrge on N, so it has more a electron - withdrawing inductive effect than Cl; m - nitrophenol will be more acidic than m - chlorophenol. Methyl group is acid weakening group. Hence the relative acidic strength is
m - cresol < phenol < m - chlorophenol < m - nitrophenol
IV I III II