1 Answer. adding more water will drive the reaction towards the products.

Summary. Three types of stresses can alter the composition of an equilibrium system: adding or removing reactants or products, changing the total pressure or volume, and changing the temperature of the system.

One way is to add or remove a product or a reactant in a chemical reaction at equilibrium. When additional reactant is added, the equilibrium shifts to reduce this stress: it makes more product. When additional product is added, the equilibrium shifts to reactants to reduce the stress.

Pure solids or liquids are excluded from the equilibrium expression because their effective concentrations stay constant throughout the reaction. The concentration of a pure liquid or solid equals its density divided by its molar mass.

Le Châtelier’s Principle states that if you apply a stress to a system at equilibrium, the equilibrium will shift in the direction that will remove the stress. Therefore, adding or removing a solid from a system at equilibrium has no effect on the position of equilibrium.

3. Importantly, water activity usually does not appear in equilibrium constant expressions for reactions in aque- ous solutions because the activity of water is near to 1 unless the solution is quite concentrated.

The value of the equilibrium constant for any reaction is only determined by experiment. As detailed in the above section, the position of equilibrium for a given reaction does not depend on the starting concentrations and so the value of the equilibrium constant is truly constant.

For a reaction involving a single reactant and single product, the equilibrium concentrations of reactant and product are unaffected by their initial concentrations. Because a catalyst accelerates the forward and reverse reactions to the same degree, it does not change the Keq of a reaction.