solubility product

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solubility product Constant which describes the product of ionic concentrations of any slightly soluble salt. The solubility of a substance is the maximum amount of that substance which can be dissolved in a solution that is in equilibrium with a solid source of the solute. The main technique for studying solubility involves the use of the solubility product, which is the total number of ions of each type in a compound that can co-exist in a solution. At a given temperature and at equilibrium the value for the solubility product will always be the same. For example, in a solution of silver chloride, AgCl dissociates to Ag+ and Cl. The solubility product Ksp is the product of their concentrations: Ksp = [Ag+][Cl] mole2/litre2. The solubility of AgCl in moles per litre is equal to the activity of Ag+ or Cl as one mole of AgCl dissolves in water to give one mole of each in solution. The value of Ksp for AgCl at 25°C is 10−9.8.