Answer
Lactic acid and lactate ion are capable of making a buffer solution with this hydronium concentration.
Work Step by Step
1. Calculate the pH value for this concentration of hydronium ion:
$pH = -log[H_3O^+]$
$pH = -log( 3.2 \times 10^{- 4})$
$pH = 3.50$
2. Using the Table 15.1, identify the conjugate pair with $pKa$ closest to $3.50$
- Lactic acid and lactate ion: $3.85$
** Remember, this difference must be lower than 1, because this is approximately the pH range of a buffer solution.
