Answer to Question #108389 in Chemistry for andrew

Question

What is the pH of Acetic Acid has a Molarity of 0.0001

Answer 1

Acetic acid = CH₃COOH

Solution:

Acetic acid (CH₃COOH) is a weak acid in aqueous media.

Therefore, CH₃COOH ionizes but less than 100% to produce protons (H⁺).

The acid dissociation constant for CH₃COOH is Ka = 1.8×10⁻⁵.

Let's set up a reaction table for the following ionization: CH₃COOH ↔ H⁺ + CH₃COO^-

Then,

x*x = 1.8*10^-5 * (0.0001 - x);

x² + 1.8*10^-5*x - 1.8*10^-9 = 0

Solving this quadratic equation, we get that x = 0.00003437 = 3.437*10^-5

x = [H⁺] = 3.437*10^-5 M.

pH = −log[H⁺].

Therefore,

pH = −log[H⁺] = −log[3.437*10^-5] = 4.46

pH = 4.46

Answer: pH = 4.46.