And we get that the concentration of the hydrogen ion in solution is equal to one times ten to negative ten when our PH is equal to 7.0. Now, by knowing what the hydrogen ion concentration is, we can also determine what the hydroxide concentration in solution is. And that's because of the following equation. So if we have a beaker of pure water, even in that beaker of pure water, water molecules will also dissociate by this same equation. So even though water is a weak acid, water molecules will still dissociate into these two ions, an H plus ion and a hydroxide ion. Now, by using basic chemistry, we can set up the equation for the equilibrium constant K. So the equilibrium constant K for this reaction is equal to the product of the concentration or the product of the concentrations of these two molecules divided by the concentration of the reactant, in this case, pure water.