Question

The dihydrogenphosphate ion, H2PO4− is amphiprotic. In which of the following reactions is this ion serving as a base?

H3O+(aq) + H2PO4−(aq) ⇌ H3PO4(aq) + H2O(l)
H3O+(aq) + HPO42−(aq) ⇌ H2PO4−(aq) + H2O(l)
H3PO4(aq) + HPO42−(aq) ⇌ 2 H2PO4−(aq)

Answer 1

Answer:

H3PO4(aq) + HPO42-(aq) ⇄ 2H2PO4-

Explanation:

In the reaction of Phosphonic acid, H3PO4 one proton H+ is removed to form dihydrogen phosphate ion, H2PO4-, which is a base.