The solubility of a sparingly soluble compound MX2 at 250C is 5.0 × 10-3 mol/L. Its solubility product at that temperature is
25 × 10-6
5.0 × 10-11
5.0 × 10-7
1.25 × 10-9
For salts of the type MX2;
Ksp = 4s3 = 45.0 × 10-33 = 5.0 × 10-7