Answer
The ${[CH_3CO_2H]}$ to ${[CH_3C{O_2}^-]}$ ratio is equal to $0.56$;
Work Step by Step
1. Calculate $[H_3O^+]$:
$[H_3O^+] = 10^{-pH}$
$[H_3O^+] = 10^{- 5}$
$[H_3O^+] = 1 \times 10^{- 5}$
2. Write the $K_a$ equation, and find the ratio:
$K_a = \frac{[H_3O^+][CH_3C{O_2}^-]}{[CH_3CO_2H]}$
$1.8 \times 10^{-5} = \frac{1 \times 10^{-5}*[CH_3C{O_2}^-]}{[CH_3CO_2H]}$
$\frac{1.8 \times 10^{-5}}{1 \times 10^{-5}} = \frac{[CH_3C{O_2}^-]}{[CH_3CO_2H]}$
$\frac{1 \times 10^{-5}}{1.8 \times 10^{-5}} = \frac{[CH_3CO_2H]}{[CH_3C{O_2}^-]}$
$0.56 = \frac{[CH_3CO_2H]}{[CH_3C{O_2}^-]}$
