Chapter 17, Problem 12E

The ${\text{H}}_{\text{2}}{\text{PO}}_{\text{4}}^{\text{-}}-{\text{HPO}}_{\text{4}}^{\text{-}}$ combination plays a role in maintaining the pH of blood.

a. Write equations to show how a solution containing these ions functions as a buffer.
b. Verify that buffer is most effective at pH 7.2.
c. Calculate the pH of a buffer solution in which $\left[{\text{H}}_{\text{2}}{\text{PO}}_{\text{4}}^{\text{-}}\right]=0.050$ M and $\left[{\text{HPO}}_{\text{42}}^{\text{-}}\right]=0.150\text{M}$ . [Hint: Focus on the second step of the phosphoric acid ionization.]