Chapter 19, Problem 81A

Interpretation Introduction

Interpretation : The amphoteric nature of hydrogen phosphate ion is to be explained with the equation.

Concept Introduction : Amphoteric refers to a substance that can function as either an acid or a base.

Answer to Problem 81A

Hydrogen phosphate ion acts as an acid as well as a base by donating and accepting protons.

  ${\text{HPO}}_4^{2-}\to {\text{H}}^{+}+{\text{PO}}_4^{3-}$

  ${\text{HPO}}_4^{2-}+{\text{H}}^{+}\to {\text{H}}_2{\text{PO}}_4^{-}$

Explanation of Solution

Amphoteric refers to a substance that can function as either an acid or a base.

The hydrogen phosphate ion is amphoteric.

Hydrogen phosphate ion act as an acid by donating its proton in the below reaction:

  ${\text{HPO}}_4^{2-}\to {\text{H}}^{+}+{\text{PO}}_4^{3-}$

Hydrogen phosphate ion act as a base by accepting its proton in the below reaction:

  ${\text{HPO}}_4^{2-}+{\text{H}}^{+}\to {\text{H}}_2{\text{PO}}_4^{-}$