So, water in the liquid states dissociates into two ions, namely H plus ion in the aqueous state and oh minus ion in the aqueous state. Notice that we have 1 mol becomes 1 mol in 1 mol. So now let's write the equilibrium constant equation. So our constant kw, which is what? We don't know where we could find that in a textbook or online. So this is something we actually know equals concentration of hydroxide times concentration of Hydride.