Chapter 11, Problem 25CI

A volume of 200.0 mL of a carbonic acid buffer for blood plasma is prepared that contains 0.403 g of ${\text{NaHCO}}_{\text{3}}$ and 0.0149 gof ${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}$ .At body temperature (37ºC), the $K_a$ of carbonic acid is $7.9\times {10}^{-7}$ . (9.4, 11.6, 11.8, 11.9)

${\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right) \rightleftarrows {\text{HCO}}_{\text{3}}{}^{-}\left(aq\right)+{\text{H}}_{\text{3}}{\text{O}}^{+}\left(aq\right)$

a. What is the $\left[{\text{H}}_{\text{2}}{\text{CO}}_{\text{3}}\right]$ ?

b. What is the $\left[{\text{HCO}}_{\text{3}}{}^{-}\right]$ ?

c. What is the $\left[{\text{H}}_{\text{3}}{\text{O}}^{+}\right]$ ?

d. What is the pH of the buffer?

e. Write a balanced chemical equation that shows how this buffer neutralizes added acid.

f. Write a balanced chemical equation that shows how this buffer neutralizes added base.