HOCl ⇌ H+ + OCl- Ka = 3.1 x 10-8 Hypochlorous acid, HOCl, is a weak acid that dissociates according to the equation above.

Write the equilibrium expression. (1 point)

Calculate the hydrogen ion concentration, [H+], of a 0.100 M solution of hypochlorous acid. (2 point)

A 0.744 g sample of sodium hypochlorite, NaOCl, is added to a 200. mL sample of a 0.100 M solution of hypochlorous acid. Assuming that no change in the volume of the solution occurs, calculate the following.

The concentration of the hypochlorous ion, OCl-, in the solution. (1 point)

The concentration of the H+ ion in the solution. (2 points)

100. mL of 0.200 M NaOH is added to the solution in part (b) to reach the equivalence point.

Write the hydrolysis reaction for the salt, NaOCl. (1 point)

Calculate the concentration of the salt, NaOCl at the equivalence point. (2 points)

Calculate the pH at the equivalence point. (4 points)

The pKa values of several indicators are given below. Which of the indicators listed is most suitable for this titration? Justify your answer. (2 points)

Indicator

pKa

Bromocresol Green

4.7

Phenol Red

7.9

Thymolphthalein

10.0