When Cl- is added to the following reaction at equilibrium, does the reaction go in the forward direction, reverse direction, or remain unchanged?

Ag-->Ag^+ + Cl^-

Are you sure the question isn't AgCl --> Ag^+ + Cl^-

Le Chatelier's Principle tells us that when we do something to a reaction in equilibrium, the reaction will shift in such as way as to undo what has been done. So if we add Cl^- to the solution, the reaction will try to undo that. How can it use Cl^-. By shifting to the _____,

Yeah, the equation was supposed to be AgCl --> Ag^+ + Cl^-. I made a typo, but based on what you said, does that mean the reaction will go in the reverse direction? I get so confused with this stuff, even though it should be rather simple.

Yes, if you add Cl^-, the reaction will shift to the left (it will go in the reverse direction and not the forward direction).

Here is the easy way to do it. It ALWAYS goes away from what was added. Adding Cl means it goes to the left (going away). Adding Ag^+ makes it go to the left (away from what was added.)
A + B + heat ==> C
adding A makes it go to the right.
Adding B makes it go to the right.
Adding C makes it go to the left.
Adding heat makes it go to the right.
Making it colder makes it go to the left (When I get one like this, I just say, OK, it I add heat it must go the right; therefore, taking heat away makes it go to the left.).
When doing gases, count the # moles on each side. Pressure shifts the reaction to the side with the smaller number of moles. In the above reaction, if A, B, and C are gases, then increasing pressure makes the reaction go to the right; decreasing pressure makes it go to the left.

To determine the effect of adding Cl- to the reaction on the direction of the reaction, we need to consider the Le Chatelier's principle. According to this principle, if we disturb a system at equilibrium, the system will try to counteract the change and shift the equilibrium position.

In the given reaction: Ag --> Ag^+ + Cl^-, the Cl- ion is being added. Since the Cl- ion is a reactant on the right-hand side, adding more reactant will shift the equilibrium position to the left in an attempt to counteract the change. Therefore, the reaction will shift in the reverse direction.

Consequently, adding Cl- to the reaction at equilibrium will cause the reaction to go in the reverse direction.