A solution is prepared by adding 500 mL of 0.3 M NaClO to 500 mL of 0.4 M HClO. What is the pH of this solution? A) The pH will be greater than the pK_a of hypochlorous acid. B) The pH will be less than the pK_a of hypochlorous acid. C) The pH will be equal to the pK_a of hypochlorous acid. D) The pH will equal the pK_b of sodium hypochlorite. E) None of these choices is correct.

Question

Quizplus · Accepted Answer

When NaClO and HClO are mixed, they form the conjugate acid-base pair NaClO/HClO. Since HClO is a weak acid (pK_a = 7.5), adding NaClO will shift the equilibrium towards the acid side, resulting in a decrease in pH. Therefore, the pH will be less than the pK_a value of hypochlorous acid.

A Solution Is Prepared by Adding 500 ML of 0