The K_aof hypochlorous acid (HClO) is 3.0 × 10^-⁸at 25.0 °C. What is the % ionization of hypochlorous acid in a 0.015- M aqueous solution of HClO at 25.0 °C?

Question

Quizplus · Accepted Answer

The equation for the ionization of hypochlorous acid is: 
HClO ⇌ H+ + ClO-
The equilibrium constant expression for this equation is: 
K = [H+][ClO-]/[HClO]
To find the % ionization, we need to calculate the concentration of H+ and ClO- ions at equilibrium, and then use these values to calculate the fraction of HClO that has ionized (i.e. formed H+ and ClO- ions).
Let x be the concentration of H+ and ClO- at equilibrium (since they are formed in a 1:1 ratio).
Then, [H+] = x
[ClO-] = x
And [HClO] = 0.015 M (initial concentration)
Substituting these values into the equilibrium constant expression and solving for x, we get: 
K = [H+][ClO-]/[HClO]
3.0 × 10^-8 = x^2/0.015
x^2 = 4.5 × 10^-10
x = 2.1 × 10^-5 M
The % ionization is then: 
% ionization = [(concentration of H+ + ClO-) / (initial concentration of HClO)] × 100%
% ionization = [(2.1 × 10^-5 M + 2.1 × 10^-5 M) / 0.015 M] × 100%
% ionization = 0.14%
Therefore, the correct answer is B) 0.14.

The Ka of Hypochlorous Acid (HClO) Is 3

The K_aof Hypochlorous Acid (HClO) Is 3