# When an inert gas is added to a system of constant volume, equilibrium is not effected?

But pressure of the system increases. Because of this increase in pressure, wouldn't (according to Le Chatelier's principal) equilibrium shift towards the side with less moles of gas?

• It would. Unless there is no such side. – Ivan Neretin Dec 27 '18 at 5:48
• @IvanNeretin not if the volume is constant. At constant volume the addition of inert gases does not influence partial pressures of the products and reactants $p_i$. It's only the total pressure that changes. Since $p_i$ do not change, no shift in equilibrium occurs. – voffch Jan 12 '19 at 10:43