The value for Ka1, and Ka2, (dissociation constants) of oxalic acid are `5.1 xx 10^(-2)` and `5.2xx10^(-5)` respectively. Give the suitable reason for the large difference in these two values.

Explanation

The large difference in the `K_(a_(1))` and `K_(a_(2))` values is due to the fact that after the removal of first H* ion, a hydrogen bond is formed between the negatively charged oxygen and hydrogen atom of the COOH group.
Thus, more energy is required to remove a proton from the anion formed in the first step than from the original oxalic acid molecule.