Well, let's see once again, what happens when we increase the concentrations of this guy and this guy. Well, recall what the reaction quotient states. If you increase the concentration of our reactants, then our reaction quotient will become larger than our equilibrium constant K. And if Q is larger than K, that means we're going to observe a rightward shift in equilibrium in other words, the forward reaction will proceed this way at a higher rate than the reverse reaction. So these guys will want to convert to decrease the overall concentration of our reactants so that our Q can become our K again. In other words, Q will tend to move towards K. Likewise, if we increase the concentration of products. That means our q will become a less than K.
And since q will want to move towards K, this concentration will tend to decreasing therefore providing a leftward shift in equilibrium.