The ionization constant, K_a, for dichloroacetic acid, HC₂HO₂Cl₂ , is 5.0 × 10^-2. What is the pH of a 0.15 molar solution of this acid?

Question

Quizplus · Accepted Answer

To find the pH, first calculate the concentration of H⁺ ions using the formula: [H⁺] = √(Kₐ × [HA]). Here, [HA] = 0.15 M and Kₐ = 5.0 × 10⁻². So, [H⁺] = √(5.0 × 10⁻² × 0.15) = √(7.5 × 10⁻³) ≈ 0.0866 M. Then, pH = -log[H⁺] ≈ -log(0.0866) ≈ 1.19.

The Ionization Constant, Ka, for Dichloroacetic Acid, HC2HO2Cl2 , Is

The Ionization Constant, K_a, for Dichloroacetic Acid, HC₂HO₂Cl₂ , Is