What is the effect of the following groups on the acidity of phenol ?
(i) `-CH_(3)` group
(ii) `-NO_(2)` group.

Explanation

(i) The presence of `-CH_(3)` group in the phenol decreases the acidity of phenol as it is an electron donating group. Therefore, it will intensify the negative charge and thus, release of a proton becomes more difficult. As a result, the acidity decreases.
(ii) Since - `NO_(2)` group is an electron withdrawing group. It disperses, the negative charge of the phenonide ion and thus stabilizes it. Therefore, `NO_(2)` group will increase the acidic strength of phenols.