posted by Anonymous .
What is the pH of a 1.00 L solution of the following buffer
0.500 M propanoic acid (HC3H5O2 Ka = 1.30 × 10^−5) / 0.800 M sodium propanoate
after the addition of 0.700 mol solid NaOH.
I tried using the Henderson-Hasselbach equation
pH = pKa + log[A-/HA]
I used it in a previous problem that used .260 mol NaOH and got a PH of 5.54 but I'm doing something wrong because I can't figure out the pH for this question no matter what I try