AP EAMCET202023 Sep 2020Morning ShiftChemistryChemical Bonding and Molecular StructureActual
The increasing order of acidic strength among the following compounds is I . Benzoic acid II . 4 - nitrobenzoic acid III . 3 , 4 - dinitrobenzoic acid IV . 4 - methoxybenzoic acid
Options
- AI < II < III < IV
- BI < IV < II < III
- CIV < I < II < III
- DIV < I < III < II
Correct answer
C. IV < I < II < III
Step-by-step solution
Since electron-donating groups decrease the acid strength, 4 - methoxy benzoic acid is a weaker acid than benzoic acid. Further, since electron-withdrawing groups increase the acid strength, both 4 - nitrobenzoic acid and 3 ,   4 - dinitrobenzoic acid are stronger acids than benzoic acid. Further, due to the presence of an additional NO 2 at m - position with respect to COOH group, 3 ,   4 - dinitrobenzoic acid, the overall acid strength increase in the order: 4 - methoxy benzoic acid < Benzoic acid