Question

With respect to acidity, how does `H_3PO_4` behave in aqueous solution?

Answer 1

Well, phosphoric acid is a fairly WEAK acid.......but in aqueous solution it is a diacid.........

Explanation:

`H_3PO_4(aq) + H_2O(l) rightleftharpoons H_2PO_4^(-) + H_3O^+`

`H_2PO_4^(2-)` does undergo some dissociation in aqueous solution.......

`H_2PO_4^(-)(aq) + H_2O(l) rightleftharpoons HPO_4^(2-) + H_3O^+`

The third dissociation is largely irrelevant and non-operative in aqueous solution........You will have to look up `pK_(a1)`, `pK_(a2)` yisself.