## Chemistry: The Molecular Science (5th Edition)

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.