The mining of seawater for magnesium, formulation of over-the-counter medicines such as antacids, and treating the presence of minerals in your home’s water supply are just a few of the many tasks that involve controlling the equilibrium between a slightly soluble ionic solid and an aqueous solution of its ions.

Now, I know that sounds rather complicated, but let me explain:

In some cases, we want to prevent dissolution from occurring. Tooth decay, for example, occurs when the calcium in our teeth dissolves. The dissolution process is aided when bacteria in our mouth feasts on the sugars in our diets to produce lactic acid, which reacts with calcium. Preventing this dissolution prevents tooth decay. On the other hand, sometimes we want a substance to dissolve. We want the calcium carbonate in a chewable antacid, the kind you may take when you have a stomachache, we want this antacid to dissolve because the ions produced in this process help soothe an upset stomach.