Two Part Solubility: The iodate ion has a number of insoluble compounds. The Ksp for AgIO₃ is 3.0 x 10⁻⁸ and the Ksp for La(IO₃)₃ is 7.5 x 10⁻¹².

Question

a. What is the solubility of AgIO₃ in a 0.125 M solution of NaIO₃?

b. What is the solubility of La(IO₃)₃ in a .125 M soution of NaIO₃?

Answer 1

Common Ion Effect:

AgIO₃(s) <==> Ag⁺(aq) + IO₃^-(aq) ... Ksp = 3.0x10^-8

Ksp = 3.0x10^-8 = [Ag⁺][IO₃^-] = (x)(0.125)

x = 2.4x10^-7 M = solubility of AgIO₃ in 0.125 M NaIO₃

La(IO₃)₃(s) <==> La³⁺(aq) + 3IO₃^-(aq) ... Ksp = 7.5x10^-12

Ksp = 7.5x10^-12 = [La³⁺][IO₃^-]³ = (x)(0.125)³

x = 3.8x10^-9 M = solubility of La(IO₃)₃ in 0.125 M NaIO₃