A buffer consists of 0.45 M CH3COOH (acetic acid) and 0.35 M CH3COONa. The Ka of acetic acid is 1.8 x 10-5 . a) Calculate the pH of the buffer solution. b) Calculate the pH after 5.0 mL of 2.0 M NaOH have been added to 400 mL of the original buffer solution.