Final answer:
To prepare a 0.10 M acetate buffer at pH 4.00, one must calculate the ratio of acetic acid to acetate ion concentrations using the Henderson-Hasselbalch equation with the given pKa and desired pH, then measure and mix the appropriate volumes of 0.10 M acetic acid and 0.10 M sodium acetate solutions.
Step-by-step explanation:
To prepare a 0.10 M acetate buffer with a pH of 4.00 using 0.10 M solutions of acetic acid and sodium acetate, we can use the Henderson-Hasselbalch equation:
pH = pKa + log([A-]/[HA])
Where pH is the desired pH of the buffer, pKa is the acid dissociation constant of acetic acid, [A-] is the concentration of the acetate ion, and [HA] is the concentration of acetic acid.
Buffer Preparation Steps:
Plug in the values into the Henderson-Hasselbalch equation to find the ratio of [A-] to [HA].
Since the desired pH (4.00) is lower than the pKa of acetic acid (4.76), there will be a higher concentration of acetic acid than acetate in the buffer.
Adjust the volumes of the acetic acid and sodium acetate solutions to achieve this ratio while keeping the total volume at 1.0 L.
The exact volumes can be calculated using molarity equations and by setting up a proportion based on the derived ratio from the Henderson-Hasselbalch equation.