The pK_a of hypochlorous acid is 7.530. A 52.0 mL solution of 0.117 M sodium hypochlorite (NaOCl) is titrated with 0.255 M HCl. Calculate the pH of the solution a) after the addition of 9.45 mL of 0.255 M HCl. pH = 11.57 b) after the addition of 25.5 mL of 0.255 M HCl. pH = 2.268 at the equivalence point with 0.255 M HCl.