Question

Increasing order of acidic strength among p=methoxy phenyl (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

The correct option is A III, I, II

The correct option is $C$.

Since $-N{O}_2$ show strong $-I$ and $-M$ effect, so it is the strongest acid. Between $I$ and $II$, $II$ is a stronger acid than $I$ because although $-C{H}_3$ shows $+I$ effect and $-OC{H}_3$ show $-I$ effect, but the inductive effect is negligible in para position. Also, $-O-C{H}_3$ group destabilizes the phenolate ions through strong $+M$effect. So, $p-$methoxyphenol is less acidic.