The common ion effect is a phenomenon in chemistry where the solubility of a compound decreases when it is dissolved in a solution that already contains one of its constituent ions.
The presence of a common ion in a solution decreases the solubility of a compound by shifting the equilibrium towards the formation of a precipitate, making it less likely for the compound to dissolve.
One common example of the common ion effect is the solubility of calcium sulfate in water. When calcium sulfate is dissolved in a solution containing calcium ions, its solubility decreases due to the common ion effect. Another example is the solubility of sodium chloride in water, which is reduced when sodium ions are already present in the solution.
The common ion effect is related to Le Chatelier's principle, which states that when a system at equilibrium is disturbed, the system will shift to counteract the disturbance. In the case of the common ion effect, the addition of a common ion to a solution containing a slightly soluble compound disturbs the equilibrium, causing the system to shift towards the formation of a precipitate.
Yes, the common ion effect can be used to control the solubility of a compound. By adding a common ion to a solution, the solubility of a slightly soluble compound can be decreased, allowing for the controlled precipitation of the compound. This can be useful in various industrial and laboratory processes.