Question

Determine the percent dissociation of a 0.18 M solution of hypochlorous acid, HCIO. The Ka for the acid is 3.5 x 10⁻⁸.

A) 3.5 x 10⁻⁶%
B) 6.3 x 10⁻⁹%
C) 7.9 x 10⁻³%
D) 4.4 x 10⁻² %
E) 1.1 x 10⁻²%

Answer 1

The percent dissociation of a 0.18 M solution of hypochlorous acid (HCIO) is 3.0%. Hence, option A) is the approx answer for this question.

Step-by-step explanation:

To determine the percent dissociation of a 0.18 M solution of hypochlorous acid (HCIO), we need to calculate the concentration of dissociated HCIO. Since HCIO is a weak acid, it will undergo dissociation into H+ and CIO-. The dissociation constant Ka for HCIO is 3.5 x 10⁻⁸.

Let's assume x is the concentration of dissociated HCIO. The initial concentration of HCIO is 0.18 M, so the equilibrium concentration will be (0.18 - x). Using the equilibrium expression for Ka, we have: [H+][CIO-] / [HCIO] = Ka. Substituting the values, we get (x)(x) / (0.18 - x) = 3.5 x 10⁻⁸.

Solving the equation, we find that x = 5.39 x 10⁻⁵ M. The percent dissociation is given by (x / initial concentration) x 100, so the percent dissociation is (5.39 x 10⁻⁵ / 0.18) x 100 = 0.02995%, which rounds to 3.0%.