Arrange the following compounds in the order of decreasing acidity
The correct option is B(iii)>(i)>(ii)>(iv) Electron withdrawing group increases the acidic strength and electron releasing group decreases the acidic strength.
NO2 has −R effect and it is the strongest electron withdrawing group. So (iii) is the most acidic. Cl has both −I and +R effect. But −I predominates over +R. Therefore (i) is the second most acidic. CH3 has hyperconjuagation effect and it is a weak acid than benzoic acid. Since it is in the ortho position and does not have ortho effect. OCH3 has a +R effect which predominates over −I effect. Hence (iv) is least acidic.