How Does The Solubility Of Magnesium Chloride Change When Other Ions Are Present?

The solubility of magnesium chloride may change when other ions are present due to the common ion effect. When an ionic compound, such as magnesium chloride, dissolves in water, it dissociates into its constituent ions. The solubility of a compound is determined by the concentration of its ions in solution and their tendency to re-associate back into the solid phase.

If another salt containing a common ion, such as sodium chloride, is added to the solution, the concentration of that ion increases. This reduces the concentration of the ion from the original magnesium chloride compound, making it less likely to dissociate and lowering its solubility. Therefore, the presence of other ions can decrease the solubility of magnesium chloride. On the other hand, if a salt containing an ion that does not appear in magnesium chloride, such as potassium sulfate, is added to the solution, the solubility of magnesium chloride is unlikely to be affected.