Question

The solubility of the ionic compound M2X3 having a molar mass of (2.0x10^2) g/mol is (1.60x10^-7) g/L. Calculate the Ksp of the compound.

Answer 1

M2X3   ----> 2M+ + 3X-
                           2s          3s

Ksp = [M+]^2 * [X-]^3
         = (2s)^2 * (3s)^3
         = 108* s^5
Here s = (1.60x10^-7) g/L / (2.0x10^2) g/mo
                = 8*10^-10 M
Ksp = 108* (8*10^-10)^5
        =3.54*10^-44
Answer: 3.54*10^-44