My textbook states that
"The addition of inert gases at constant volume does not affect the equilibrium state of the reactants and products contained in that volume."
Although I am not questioning the truth behind this statement, I am very confused by it.
Let us consider a homogeneous gaseous equilibrium system contained within a closed cylinder. The cylinder has a very small hole on its side, through which an inert gas can be pumped in. This is how I visualize the addition of an inert gas to the system. Now, upon introducing a given amount of inert gas into the system, how does the volume remain constant in any way?
While deriving Van der Waals equation for real gases, I learned that the term $V$ in the ideal gas equation stands for the empty space that is available to the gas molecules for movement. Therefore, when we introduce an inert gas into the system, aren't we essentially decreasing this amount of space that is available to the reactant and product molecules for movement?
I am very confused. Please share your insights for it would be tremendously helpful for me. Thanks ever so much in advance :) Regards.