Answer:
Ka = 1.8 × 10⁻⁵
Explanation:
Acetic acid is a weak acid that dissociates according to the following equation.
HCH₃CO₂(aq) ⇄ CH₃CO₂⁻(aq) + H⁺(aq)
The concentration of the acid is Ca = 1.4 M.
The pH is 2.30. The concentration of H⁺ is:
pH = -log [H⁺]
[H⁺] = anti log (-pH) = anti log (-2.30) = 5.01 × 10⁻³ M
We can find the acid dissociation constant (Ka) using the following expression.
[H⁺] = √(Ca × Ka)
Ka = [H⁺]²/Ca
Ka = (5.01 × 10⁻³)²/1.4
Ka = 1.8 × 10⁻⁵
