Question

Increasing order of acidic strength among p-methoxy phenol (I), p-methyl phenol (II) and p-nitrophenol (III) is

• A. III, I, II
• B. II, I, III
• C. III, II, I
• D. I, II, III

Answer 1

Answer: (C)

III, II, I

Answer 2

Nitro group is an electron-withdrawing group, so increase the acidic character of phenol whereas $-CH_3$ and $-OCH_3$ both are electron releasing groups, so it decrease the acidic character of phenol but $-CH_3$ group is less electron donating or releasing, so p-methyl phenol is slightly more acidic than p-methoxy phenol and p-nitro phenol is most acidic.
So the order of acidic character is p-methoxy phenol < p-methyl phenol $50mm$ < p-nitro phenol.