Answer
Acetic acid and acetate ion are capable of making a buffer solution with this hydronium concentration.
Work Step by Step
1. Calculate the pH value for this hydronium ion concentration:
$pH = -log[H_3O^+]$
$pH = -log( 5.0 \times 10^{- 5})$
$pH = 4.30$
2. Using the Table 15.1, identify the conjugate pair with $pKa$ closest to $4.30$
- Acetic acid and acetate ion: $4.74$
** Remember, this difference must be lower than 1, because this is approximately the pH range of a buffer solution.
