The water–gas shift reaction CO1g2 + H2O1g2Δ CO21g2 + H21g2 is used industrially to produce hydrogen. The reaction enthalpy is H = -41 kJ. (b) Could you increase the equilibrium yield of hydrogen by controlling the pressure of this reaction? If so would high or low pressure favor formation of H2(g)?

Video transcript

hi everyone for this problem, it reads hydrogen gas and iodine gas react to form gasses, hydrogen iodide. Would a change in pressure affect the yield of the reaction If yes, would an increase or decrease in pressure favor the formation of hydrogen iodide. Okay, so for this question we want to answer whether or not a change in pressure is going to affect the yield of our reaction. So we have a reaction that is at equilibrium and so we're dealing with outliers principle here, which tells us when we have an equilibrium or a system that's at equilibrium and a stress is put on that system. The system is going to readjust to maintain its equilibrium state and in this particular instance, our stress is a change in pressure. So we need to understand how does change in pressure affect the yield of our reaction. So the first thing we need to know is that if we have an increase in pressure, this is going to cause our reaction to want to shift to fewer moles of gas. Okay, on the other hand, if we have a decrease in pressure that is going to cause our reaction to want to shift to the side with more moles of gas to offset that. Okay, and so we want to know if an increase or decrease in pressure will favor the formation of hydrogen iodide. So let's go ahead and rewrite out our equation. So we can see what is going on. Okay, so the first thing that we want to do is see how many moles we're dealing with of reactant and product because like we said, an increase or decrease in pressure is going to favor either the fewer moles of gas or the more moles of gas on each side. So on our reactant side we have two moles. And on our product side we also have two moles. Okay. And so our change in the number of moles. So this is represented by delta N. R. Change in number of moles is zero. Okay, so what this means is pressure will not affect the equilibrium reaction. So our answer to this problem is no, a change in pressure will not affect the equilibrium yield. Okay, so that is the answer to this problem and that is the end of this problem. I hope this was helpful.