the answer is c. Gas molecules will never collide with the walls of the container
So scientist around the world can share there info without having to convert and doing extra work.
The wick and the wax
Sorry if that was useless, I'm not sure how generalized you were being
Presuming the arrow is between H20 and CO
On the left there are 2 gas moles.
On the right there are 4 gas moles.
The equilibrium will shift to the side with the most no. He gas moles when pressure is decreased.
Therefore the answer is A, since 4>2.
If you have any questions, feel free to ask