Questions regarding Equilbrium and Le Chantelier's principle

[dream chaser]

Hi Guys,

For the reaction: CH3OH(g) + HBr(g) -> CH3Br(g) + H2O(g)
                                                           <-
Considering the system at equilibrium, what would happen to the percentage yield of bromomethane when you are continuously removing the product CH3Br.

My understanding: I know that by according to Le Chatelier's principle, the system will partially oppose the effect of removing CH3Br by adding CH3Br. In doing so, the reaction would shift to the product side as the concentration of the products would increase and the concentration of the reactants would decrease. Hence, the position of equilibrium shifts to the right.

What I don't understand is even though CH3Br is being added due to Le Chaterlier's principle, its concentration would never reach the same as it was at first equilibrium. If that is the case, wouldn't you say the percentage yield of bromomethane would have decreased rather than increased?

Thanks. All help will be much appreciated.

[Rom_Dog]

Hey!

You're correct in saying that the equilibrium shifts towards the product side. The percentage yield of bromomethane is said to increase as when you continuously remove this product, you will have more bromomethane than if you just removed the product once and didn't do anything else to the system. While the percentage yield of bromomethane increases, it's concentration is decreasing as more bromomethane is being extracted from the system. It is true that the amount of bromomethane you extract each time the system reaches equilibrium is less however the total amount of extracted bromomethane is still increasing thus your percentage yield is increasing.

I hope this helps!

- Rom