Now, if we take this expression, the log and bring it to the left side, we get our Henderson Hasselbalk equation. So what this equation tells us is the PH of our solution that contains that Buffet system is equal to the PKA value of that particular asset that is used in that buffer system, plus the log of the ratio of the conjugate base to its acid. Now, why is this equation a useful equation? Well, let's get back to it in just a moment. Let's go back to this graph for just a second. So earlier I said that this particular curve describes an acid that is acetic acid and a base that is acetate ion.