Step-by-step explanation:
If the pressure of the system increases, the equilibrium will shift towards the side of the reaction with fewer moles of gas.
There are only gases on both sides of the reaction.
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On the left, there are: 2 moles CO + 1 mole O2 => in total = 3 moles
On the right, there are: only 2 moles of CO2
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The equilibrium will shift to the right because of the fewest moles. Therefore, the quantity of CO2 will increase.
Answer: The quantity of CO2 (g) increases.