The addition of a catalyst to an equilibrium system is a final stress factor. We consider how adding a catalyst affects the following: \[\ce{N_2(g) + O_2(g) \leftrightharpoons 2NO(g)} \nonumber \] Adding a catalyst to this, or any other equilibrium system, will not affect the position of an equilibrium. A catalyst speeds up both the forward and the reverse reactions, so there is no uneven change in reaction rates. Generally, a catalyst will help a reaction to reach the point of equilibrium sooner , but it will not affect the equilibrium otherwise.