Solubility
product constants are values to describe the saturation of ionic compounds with
low solubility. A saturated solution is when there is a dynamic equilibrium
between the solute dissolved, the dissociated ions, the undissolved and the
compound. It is calculated from the product of the ion concentration in the
solution. For the generic salt, AB2, the dissociation would be as
follows:
AB2 = A2+ + 2B-
So, the expression for the solubility product would be:
Ksp = [A2+] [B-]^2
Ksp = [x] [2x]^2 = 4x^3
where x = 3.72×10^−4 M
Ksp = 4( 3.72×10^−4 )^3
Ksp = 2.06x10^-10 M^3
The solubility product constant of AB2 would be Ksp = 2.06x10^-10 M^3.
