In the reaction below:


Increasing the concentration of Cl2 will _____ at equilibrium.



HAVE NO EFFECT

This is the equation

PCl3 + Cl2 = PCl5

You need to review Le Chatelier's Principle. I think the definition given in text books is so esoteric and it really sounds good to me. However, I find that most students don't understand it. I don't know why but here is my definition. Not nearly so esoteric but students usually get it. Ready?

Le Chatelier's Principle says this. When we do something to a chemical system in equilibrium, the reaction will try to undo what we did. Got that? How does that apply to this equation?
PCl3 + Cl2 ==> PCl5

So here is a system at equilibrium. We add more Cl2, the reaction tries to undo what we did. How can it do that you say. It can move the reaction to the right to form more PCl5 because that way will use up at least some of the Cl2 we added. PCl5 will increase, PCl3 will decrease and Cl2 will decrease from the total that's there now (the original + what we added extra) although it can't get rid of ALL of the extra Cl2 we added. This argument works for adding or taking away heat, adding concns of products or reactants. For gaseous reactions, pressure is involved and for that one you just remember that increasing P will shift the equilibrium to the side with the fewer moles.

Increasing the concentration of Cl2 will have no effect at equilibrium.

To determine the effect of increasing the concentration of Cl2 on the reaction at equilibrium, we need to consider Le Chatelier's principle. According to this principle, if we disturb a system at equilibrium, the system will adjust itself to minimize the effect of the disturbance.

In this case, increasing the concentration of Cl2 will disturb the equilibrium. To understand why it has no effect on the reaction, we need to examine the balanced chemical equation and the stoichiometry of the reaction.

Without the specific reaction provided, it is difficult to determine the exact effect of increasing the concentration of Cl2. However, based on the general principles, if Cl2 is not involved in the reaction or if it is present in excess, increasing its concentration will have no effect on the equilibrium position.

To fully answer the question, it is necessary to evaluate the stoichiometry and equilibrium constant of the reaction. By doing so, we can determine whether the concentration of Cl2 affects the equilibrium position (shifts to the left or right) or if it remains unaffected.

In conclusion, we cannot determine the effect of increasing the concentration of Cl2 on the reaction at equilibrium without further information about the specific reaction and its equilibrium constant.