Factors that DO affect equilibrium:
* Temperature: Increasing temperature favors the endothermic reaction (heat is absorbed), and decreasing temperature favors the exothermic reaction (heat is released).
* Concentration: Changing the concentration of reactants or products will shift the equilibrium to counteract the change.
* Pressure: Changes in pressure primarily affect reactions involving gases. Increasing pressure favors the side with fewer moles of gas, and decreasing pressure favors the side with more moles of gas.
* Addition of a Catalyst: A catalyst speeds up the rate of both forward and reverse reactions equally, so it does not affect the position of equilibrium. It simply helps the equilibrium to be reached faster.
Therefore, the answer to the question is: Addition of a catalyst.
Important Note: While a catalyst doesn't change the position of equilibrium, it does affect the rate at which equilibrium is reached.
