7.12 Common-Ion Effect

Identify the solubility of a salt, and/or the value of Ksp for the salt, based on the concentration of a common ion already present in solution.

• The solubility of a salt is reduced when it is dissolved into a solution that already contains one of the ions present in the salt. The impact of this “common-ion effect” on solubility can be understood qualitatively using Le Châtelier’s principle or calculated from the Ksp for the dissolution process.