Answer:
The molar solubility can be used to calculate the concentrations of ions in solution, which in turn are used to calculate Ksp.
Explanation:
Consider a slightly soluble solid with formula M₃X₂. Its solubility product expression is
[tex]\begin{array}{rcccc}M_{3}X_{2}(s) & \rightleftharpoons&3M^{2+}(aq) & + & 2X^{3-}(aq)\\& & 3s & &2s\\\\K_\text{sp}& = & [3s]^{3}[2s]^{2}&= & 108s^{5}\\\\\end{array}[/tex]
Thus, the molar solubility can be used to calculate the concentrations of ions in solution, which in turn are used to calculate Ksp.
A is wrong. The solubility product constant is a constant. It does not change in the presence of a common ion.
B is wrong. It is correct only for compounds with formula MX.
C is wrong. Ksp does not equal the concentration of the compound in solution.