posted by craig .
How does the presence of a common ion affect the solubility of a salt? Explain in terms of equilibrium.
I can help you through this but I don't want to write it for you. The common ion effect is just an example of Le Chatelier's Principle.
Oh that's what it is? Thanks
Right. The "common ion effect" is called that because there is a "common ion."
For example, Ag2CrO4 ==> 2Ag^+ + CrO4^2-
So if we add AgNO3 the Ag^+ is the common ion.
If we add Na2CrO4 the CrO4^2- is the common ion. Both decrease the solubility of Ag2CrO4