Solubility Product Constant What is Ksp? Relationship

Go here to visualize salt dissolving in water.

Solubility Product Constant (Ksp) Solubility Product Constant, Ksp is the equilibrium constant for a solid substance dissolving in an aqueous solution. It represents the level at which a solute dissolves in solution. The more a substance dissolves, the higher the Ksp value it has.

Solubility Products Consider the equilibrium that exists in a saturated solution of BaSO4 in water: BaSO4(s) Ba2+(aq) + SO42−(aq) The equilibrium constant expression for this equilibrium is Ksp = [Ba2+] [SO42−] where the equilibrium constant, Ksp, is called the solubility product.

Oh – you mean like solubility? Ksp is not the same as solubility. Solubility is generally expressed as: - mass of solute dissolved in volume (g/mL) - mol/L (M).

PbCl2(s)  Pb2+(aq) + 2 Cl-(aq) Example 1 Calculate the solubility product constant for lead(II) chloride, if 50.0 mL of a saturated solution was found to contain 0.2207 g of lead (II) chloride dissolved in it. Write reaction and Ksp expression. PbCl2(s)  Pb2+(aq) + 2 Cl-(aq) Ksp = [Pb2+][Cl-]2

Example 1 Calculate the solubility product constant for lead(II) chloride, if 50.0 mL of a saturated solution was found to contain 0.2207 g of lead (II) chloride dissolved in it. Convert to Molarity! 0.0159 M PbCl2 ICE TABLE! Ksp = [0.0159][0.0318]2 = 1.61 x 10-5

Example 2 (Other Direction) Estimate the solubility of Ag2CrO4 in pure water if the solubility product constant for silver chromate is 1.1 x 10-12 Write reaction and Ksp expression. Ag2CrO4(s)  2 Ag+(aq) + CrO42-(aq) Ksp = [Ag+]2[CrO42-]

Example 2 (Other Direction) Estimate the solubility of Ag2CrO4 in pure water if the solubility product constant for silver chromate is 1.1 x 10-12 Let "x" be the number of moles of silver chromate that dissolves in every liter of solution (mol assuming 1 L) ICE TABLE! 1.1 x 10-12 = [2x]2[x] x = 6.50 x 10-5 M