What is the solubility of Cd₃(PO₄)₂ in water? (Ksp of Cd₃(PO₄)₂ is 2.5 × 10⁻³³)

Answer 1

Cd₃(PO₄)₂(s) <===> 3Cd²⁺(aq) + 2PO₄^3-(aq)

Ksp = [Cd²⁺]³[PO₄^3-]²

Let x = [PO₄^3-]. Then [Cd²⁺] = 3/2 x = 1.5x

2.5x10^-33 = (1.5x)³(x)²

2.5x10^-33 = 3.375x⁵

x⁵ = 7.41x10^-34 ... (be sure to check my math)

x = 2.37x10-6 M = [PO₄^3-]

Solubility Cd₃(PO₄)₂ = 1/2 * 2.37x10^-6 M = 1.19x10^-6 M