Using the pH of the acetic acid solution before addition of any NaOH and the experimentally determined precise concentration of the acetic acid solution, determine pKa for acetic acid. Calculate and report the percent error in your pKa value.
Initial pH: 2.91
Concentration of the acetic acid solution: 0.09887M
(Note: this is a post-lab question about titration of acetic acid with NaOH)