This page presents basic problems involving the common ion effect in solubility equilibria. Since it's an introduction, all of the problems will fit the approximatiom model; that is, you can view the common ion concentration as coming solely from the soluble material. The other ion will come solely from the slightly soluble material. Pressing "New Problem" will cause a question to appear. Determine the value of the answer, enter it in the answer cell and press "Check Answer". Results will appear in the table. Pressing "Show Answer" will display the solution and you will no longer be able submit an answer for that problem.