Question

The solubility of copper (ii) oxalate is 3.2 x 10^-3 g/L. What is the solubilty product constant for copper (ii) oxalate?

Answer 1

Using molar mass, convert those grams into moles

151.57 gm of copper (II) oxalate = 1 mole

3.2 x 10^-3 gm of copper (II) oxalate = (3.2 x 10^-3) / (151.57) mole = 2.11 x 10^-5

Since,

1 mole CuC2O4 releases 1 mole Cu⁺² & 1 mole (C₂O₄)^-2

2.11 x 10^-5 Molar CuC₂O₄ releases 2.11 x 10^-5 Molar Cu⁺² & 2.11 x 10^-5 Molar (C₂O₄)^-2

Ksp = [Cu⁺²] [C₂O₄^2-]

Ksp = [2.11 x 10^-5] [2.11 x 10^-5]

Ksp = 4.452 x 10^-10

Rounding upto 2 sig figs is
Ksp = 4.5 X 10^-10