Which of the following factors would NOT shift the equilibrium position?

In this context, adding a catalyst does not shift the equilibrium position of a chemical reaction. A catalyst increases the rate of both the forward and reverse reactions equally, allowing the system to reach equilibrium faster but not changing the actual position of the equilibrium. This means that the concentrations of reactants and products at equilibrium remain unchanged.

Conversely, changing the concentration of products or reactants, or altering the pressure in a gaseous system, all impact the equilibrium. According to Le Chatelier's principle, if the concentration of reactants or products changes, the equilibrium will shift in the direction that counteracts the change. For example, increasing the concentration of reactants will shift the equilibrium toward the products, whereas lowering the concentration of products will shift it toward the reactants. In gaseous systems, changing pressure typically affects equilibrium if the number of moles of gas on either side of the reaction is different, leading to a shift toward the side with fewer moles of gas to relieve the pressure stress.