Why does the addition of an inert gas to a constant-volume equilibrium mixture of gases not disturb the equilibrium? view available hint(s) why does the addition of an inert gas to a constant-volume equilibrium mixture of gases not disturb the equilibrium? the pressure is increasing on both sides of the reaction equally; thus the equilibrium does not shift. addition of the inert gas prevents the reaction from occurring in the same fashion as before the addition. the partial pressures and/or concentrations of reactants and products are not affected by the presence of other gases. an inert gas is unreactive and thus won't affect the equilibrium?