Identify the correct decreasing order of acidic strength for the following compounds: (i) (ii) (iii)

Step-by-step solution

The given compounds are: (i) 2,4-dinitrobenzoic acid (ii) 3,4-dinitrobenzoic acid (iii) 3,5-dinitrobenzoic acid The acidic strength of substituted benzoic acids is enhanced by the presence of electron withdrawing groups. The NO₂ group exerts strong -I and -M effects. Compound (i) possesses an NO₂ group at the ortho position. Due to the ortho effect, it is significantly more acidic than the other isomers. The additional NO₂ group at the para position further increases its acidic strength. Hence, (i) is the most acid