What is the Ka value of acetic acid from the pH of the buffered solution? pH=4.39 of 25ml of HC2H3O2 with .410g NaC2H3O2 added.

Ka = [H3O][C2H3O2] / [HC2H3O2]

1 answer

Use the Henderson-Hasselbalch equation.
pH = pKa + log[(base)/(acid)]
Solve for pKa and convert to Ka.