Question

how will you explain trichloro acetic acid is stronger then acetic acid

Answer 1

When an chlorine atom, which is an electron withdrawing group is present in the chain attached to a carboxyl group, it exerts -I effect and withdraws electrons from the carbon of the carboxyl group as well as from the oxygen of the O-H bond. This decreases electron density at the oxygen atom of the O-H bond. Consequently, the O-H bond gets weakened and the release of H+ ion is favored. Moreover, the negative charge present on the carboxylate ion gets dispersed and its stability is increased. Thus, the acid strength of the acid increases. So now the H+ atom can easily come out and the stability of the carboxylate ion has also increased. Hence both the conditions make chloroacetic acid more acidic than acetic acid.

Inductive effect is responsible for the acidity of chloroacetic acid .