The equilibrium position of a chemical reaction can change with an increase or decrease in pressure according to Le Chatelier's principle. This principle states that if a system at equilibrium is subjected to a change in pressure, temperature, or concentration of reactants and products, the system will adjust its equilibrium position to counteract the change.For reactions involving gases, an increase in pressure will shift the equilibrium position towards the side with fewer moles of gas, while a decrease in pressure will shift the equilibrium position towards the side with more moles of gas.Let's consider the following example of a chemical reaction:N2 g + 3H2 g 2NH3 g In this reaction, nitrogen gas N2 reacts with hydrogen gas H2 to form ammonia gas NH3 . The total number of moles of gas on the reactant side is 4 1 mole of N2 + 3 moles of H2 , while the total number of moles of gas on the product side is 2 2 moles of NH3 .If the pressure of the system is increased, the equilibrium position will shift towards the side with fewer moles of gas, which is the product side formation of NH3 . This is because the system will try to counteract the increase in pressure by reducing the number of gas particles, thus reducing the pressure.On the other hand, if the pressure of the system is decreased, the equilibrium position will shift towards the side with more moles of gas, which is the reactant side formation of N2 and H2 . This is because the system will try to counteract the decrease in pressure by increasing the number of gas particles, thus increasing the pressure.In summary, the equilibrium position of a chemical reaction involving gases can change with an increase or decrease in pressure, shifting towards the side with fewer or more moles of gas, respectively, according to Le Chatelier's principle.