Answer to Question #108387 in Chemistry for andrew

Question

What is the pH of 0.23 M HClO2

Answer 1

Solution:

HClO₂ is a weak acid in aqueous media.

Therefore, HClO₂ ionizes but less than 100% to produce protons (H⁺).

The acid dissociation constant for HClO₂ is Ka = 1.1*10^-2.

Let's set up a reaction table for the following ionization: HClO₂ ↔ H⁺ + ClO₂^-

Then,

1.1*10^-2 * (0.23 - x) = x*x;

x² + 0.011*x - 0.00253 = 0

Solving this quadratic equation, we get that x = 0.0451

x = [H⁺] = 0.0451 M.

pH = −log[H⁺].

Therefore,

pH = −log[H⁺] = −log[0.0451] = 1.3458 = 1.35

pH = 1.35

Answer: 1.35 is the pH of 0.23 M HClO₂.