What is the solubility of La(IO₃)₃ in a solution that contains 0.200 M La³⁺ ions? (Ksp of La(IO₃)₃ is 7.5 × 10⁻¹²)

Answer 1

Common Ion Effect:

La(IO₃)₃(s) <==> La³⁺(aq) + 3IO₃^-(aq)

Ksp = [La³⁺][IO₃^-]³

7.5x10^-12 = [0.200][IO₃^-]³

[IO₃^-]³ = 9.4x10^-10 M

[IO₃^-] = 9.8x10^-4 M

Solubility of La(IO₃)₃ = 1/3 x 9.8x10^-4 M = 3.3x10^-4 M