Solubility of salts can be determined knowing the expression of the solubility product, ksp, and its value. Ksp is equal to the product of the equilibrium ion concentraions in soluion, each raised to the power of the coeicient in the balanced equaion for dissoluion of the solid salt. The ksp equaion also allows you to determine the solubility of a salt when the concentraion of one of the ions, called a common ion, is varied independently by addiion of a second salt. You should be able to: calculate the solubility of a salt knowing its ksp value, and vice versa, recalculate solubility of ionic solids in soluions containing a certain concentraion of a. Common ion. : predict the order in which precipitaion of salts of several metal ions takes place upon drop wise addiion of a soluion containing an anion that forms salts with these metal ions that are not very soluble.