# Using Le Chatelier's Principle [duplicate]

The following reaction is allowed to reach equilibrium. $$\text{CoBr}_2(g)\rightleftarrows\text{CO}(g)+\text{Br}_2(g)$$ What happens to the reaction when inert argon gas, $$\text{Ar}(g)$$, is added?

The solution to this problem states that the addition of an inert gas would not change the concentrations of the other gases, and therefore, the reaction is still at equilibrium.

However, won't adding the argon result in an increase in the pressure of the system, and, to restore the equilibrium, the number of molecules should be reduced and the reverse reaction would be favored? Can someone please explain?

• This an example of a problem with incomplete information. You either have to assume that the pressure is constant or it isn't. If you assume that the pressure is constant then the equilibrium doesn't change. If you assume that the pressure increases then the equilibrium does change. – MaxW Feb 24 '19 at 0:07
• Shoudn't be this compound bromophosgene? (not cobalt bromide as written). – Mathew Mahindaratne Feb 24 '19 at 2:04