And so, since this guy remains the same throughout the experiment going this way, that means our rate also begins to diminish going from X to Y. How about going from Y to X? Well, going from Y to X, our concentration of that product begins to increase. And that means as the reaction is going this way, we're getting more of y. That means our Y, our rate law for going from the products to reactants begins to increase the rate of reaction, rate of reverse reaction. That's because the concentration of Y begins to increase.