In completing a Fischer Esterification experiment using acetic acid and unknown alcohol catalyzed by sulfuric acid a student starts with excess acetic acid with the intention of shifting the equilibrium towards formation of product. Identify the law used to predict this effect.

The equilibrium law

Explanation:

According to the equilibrium law , when of any of the  reactants or the products in the reaction at an equilibrium state,  is changed, then it changes the composition of equilibrium mixture in order to minimize the effect of

Acetic acid (in excess) + ⇄   + water

is a reaction which involves the equilibrium. So to force the reaction towards the side of , one of the reactant is taken in excess. All this can be explained easily by applying the equilibrium law.