Question

The p K a of hypochlorous acid is 7.530 . A 60.0 mL solution of 0.103 M sodium hypochlorite ( NaOCl ) is titrated with 0.296 M HCl . Calculate the pH of the solution after the addition of 8.00 mL of 0.296 M HCl .

Answer 1

Answer:

pH of the solution after addition of 8 ml 0,296 molar HCl = 7.94

Explanation:

In this case buffer exist between hypochlorous acid HClO is a weak acid and its conjugate base hypochlorite ion ClO⁻ which are deliver to the solution by NaOCl ( sodium hypochlorite ).

The salt is completely dissociate

                     [NaOCl] = [ClO⁻]

Using Henderson equation to find pH of this buffer

            pH = pKa + log$\frac{[Conjugate base]}{[Acid]}$

or,               = 7.53  + log$\frac{60 X 0.103}{8 X 0.296}$

or,               = 7.53 + 0.4

or,               = 7.94