Question

Increasing order of acid strength among p-methoxy phenol, p - methyl phenol and p - nitro phenol is:

• A. p - methyl phenol < p - methoxy phenol < p - nitro phenol
• B. p - methoxy phenol < p - methyl phenol < p - nitro phenol
• C. p - nitro phenol < p - methoxy phenol < p - methyl phenol
• D. p - nitro phenol < p - methyl phenol < p - methoxy phenol

Answer 1

The correct option is A p - methyl phenol < p - methoxy phenol < p - nitro phenol

Increasing acid strength:


Acidic strength $\alpha -R,-H,-I$
Acidic strength $\alpha \frac{1}{+R,+H,+I}$
where
R = Resonance effect
H = Hyperconjugation effect
I = Inductive effect
$-N{O}_2$ shows $-R_1-I$
$-OC{H}_3$ shows $+R_1-I$
$-C{H}_3$ shows $+H_1+I$