Calculate the value of dissociation constant of weak acid, which dissociates to 0.01 % in its 0.1 M solution?

Step-by-step solution

Given a weak acid with initial concentration C = 0.1 M and percentage dissociation 0.01 % , the degree of dissociation is = 0.0001 = 1 10⁻⁴ . For weak acid dissociation HA H^+ + A^- , and under the approximation 1 - 1 when is small, the dissociation constant simplifies to K_a = C ^2 . Substituting the values: K_a = (1 10⁻¹) (1 10⁻⁴)^2 = 10⁻⁹ . The calculated value K_a = 10⁻⁹ corresponds to option D .