Effect of pressure

[405773279]

When increasing pressure, the concentration increases and in accordance with the Le Chatalier's Principle, the conc of the substance previously less abundant increases right? For the solution of Q 5.33 in the textbook, it says that increase in pressure is not responsible for the change shown in the question. I'm not sure if im misinterpreting the effect of pressure or the question. Could someone help me out?

[Dayeon Kim 2D]

You are correct in your interpretation of the effects of pressure according to Le Chatelier's principle which is the side of the reaction that has less moles is favored with the increase of pressure. In terms of the question, it is asking to choose between a, b, c, and d to explain why in the second diagram there are more X molecules than X2. None of those choices were pressure. And even if there were pressure it would not be correct because it is shown that in the equation the reactant side has less moles making it be the side that is favored if pressure was increased.

[Brianna Bui 2J]

Hi!

Just wanted to add that it depends on how the change in pressure is created. If it is by pumping in an inert gas like He, there shouldn't be a change in the equilibrium because inert gases are not reactive. If the pressure change was due to a change in volume, like a piston chamber decreasing the volume, then there would be a shift in the reaction to accommodate the changes. It is important to remember though that changes in Temperature are the only physical changes that effect the equilibrium constant.