Le Chatelier's Principle: Equilibrium Shift with Pressure Change

[youmei0426]

Homework Statement

Homework Equations

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The Attempt at a Solution

I know that the equilibrium will shift to the side with fewer moles of molecules when the pressure is increased according to le Chatelier's principle, so I thought in this case it would shift to the left as there is only 1 mole of gaseous atom compared to 2 moles on the right-hand side. The answer is A, however. Thanks in advance!

 

[Lord Jestocost]

H⁺(aq) and HCO₃^-(aq) are ions in the aqueous solution.

 

[Borek]

I know that the equilibrium will shift to the side with fewer moles of molecules when the pressure is increased

As worded it is true for gases only, not in general.

As @Lord Jestocost already hinted, check state of all present substances. How many are gases?

 

[epenguin]

Time to say after half a century I have always hated from the very beginning this expression "The equilibrium shifts to the left (or the right)." I at first indeed did not know what that meant, well I picked it up from the way the teacher repeatedly used it, but I do not think it is good wording. That said, you will meet it.

The way I think is, there is something that is constant, the equilibrium constant.
In this example there is another thing that you can take as constant, the concentration of water.
That being so, and looking at your equation and looking also the corresponding equation that defines the equilibrium constant, when the pressure of CO₂ increases, what else must change and how?

I think that is a better way of thinking than being bamboozled by words.