Common ion effect=Le Chat

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
They are related to each other. Common ion effect just says that if there is an ion in solution and you add more of that ion, the reaction shifts to counteract the addition of the ion by shifting the equilibrium in the opposite direction.
 
The common ion effect is a general principle of equilibrium applied to salt dissociation.

In general: the presence of a product will reduce how much of a reactant can go forward in a reaction.

Common ion effect: the presence of an ion of the salt in solution (a product) will reduce how much of a salt (a reactant) can dissociate (go forward in a reaction).
 
Simple example: PbI2 <-> Pb(2+) + 2I- with Ksp = 7.1×10–9

If I add KI to solution, how does this push the reaction above?
 
Top