Question

Compare propionic acid and benzoic acid according to their acidic strength​

Answer 1

Answer:

Since, electron donating groups decreases the acid strength, therefore, 4-methoxy benzoic acid is a weaker acid than benzoic acid. Further, since electron-withdrawing groups increase the acid strength, therefore, both 4-nitrobenzoic acid and 3, 4-dinitrobenzoic acid are stronger acid than benzoic acid.

Further, due to presence of an additional NO

2

at m-position with respect to COOH group, 3, 4-dinitrobenzoic acid thus the overall acid strength increase in the order:

4-methoxy benzoic acid < benzoic acid < 4-nitrobenzoic acid < 3, 4-dinitrobenzoic acid.