# How does an equilibrium shifts if product is added to a reaction?

For $A + B r i g h t \le f t h a r p \infty n s C + D$, if more product is added, the equilibrium will move so as to offset the external perturbation, and move to the left as written. This is a restatement of Le Chatelier's principle: a system at equilibrium when subject to an external perturbation will move so as to offset the external perturbation (and again note that $\text{offset"!="counteract}$).