In a reaction at equilibrium in which reactants and products are gases, pressure is a factor that produces a shift of the equilibrium position. When the pressure is increased, the equilibrium is shifted to the side of the reaction with a fewer moles. In this reaction:
2 HD(g) ⇀↽ H₂(g) + D₂(g)
There is the same number of moles on both sides:
reactants side: 2 moles HD
products side: 1 mol H₂ + 1 mol D₂ = 2 moles
Therefore, the equilibrium position will not change.
