Answer
The base/acid concentration ratio in blood is equal to 20.
Work Step by Step
1. Calculate $[H_3O^+]$:
$[H_3O^+] = 10^{-pH}$
$[H_3O^+] = 10^{- 7.4}$
$[H_3O^+] = 4 \times 10^{- 8}$
2. Write the $K_a$ equation, and find the ratio:
$K_a = \frac{[H_3O^+][HC{O_3}^-]}{[H_2CO_3]}$
$7.9 \times 10^{-7} = \frac{4 \times 10^{-8}*[HC{O_3}^-]}{[H_2CO_3]}$
$\frac{7.9 \times 10^{-7}}{4 \times 10^{-8}} = \frac{[HC{O_3}^-]}{[H_2CO_3]}$
$20 = \frac{[HC{O_3}^-]}{[H_2CO_3]}$
