The solubility of Mg(OH)2, in water at 25 ° is measured to be 0.0096 g/L. Use this information to calculate Ksp for Mg(OH)2.

Question

The solubility of Mg(OH)₂, in water at 25 ° is measured to be 0.0096 g/L. Use this information to calculate K_sp for Mg(OH)₂.

Round your answer to 2 significant digits.

Answer 1

molar mass Mg(OH)₂ = 58.32 g / mol

0.0096 g / L x 1 mol / 58.32 g = 1.65x10^-4 mol/L

Mg(OH)₂(s) <==> Mg²⁺(aq) + 2OH^-(aq)

Ksp = [Mg²⁺][OH^-]²

[Mg²⁺] = 1.65x10^-4 M

[OH-] = 2 x 1.65x10^-4 = 3.29x10^-4 M

Ksp = (1.65x10^-4)(3.29x10^-4)²

Ksp = 1.8x10^-11