Question

Why formic acid is stronger than acetic acid?

Answer 1

1. The negatively charged acetate ion (i.e the conjugate base of acetic acid) gets destabilised by + I effect of - CH₃ group.
2. Lesser is the stabilisation of the conjugate base. weaker is the acid.
3. In formate ion, there is no such destabilisation effect. Thus. formic acid is stronger than acetic acid.