So we're left with hydronium concentration times the hydroxide concentration. And if you go back to the video for Autoinization of War, which you'll find right here, you'll see that this guy simply equals kw. So we see that when we multiply ka times KB, what we get is kw. So this is an important relation. Now, what happens if we take the log of both sides? Well, if we take the log of both sides, we get PKW is equal to PKA plus PKB.