If Kc ≫ 1 for a reaction at a given temperature, does the equilibrium favor products or reactants?

• A. Favors products
• B. Favors reactants
• C. No preference
• D. Favors products

Answer: (A)

When the equilibrium constant expresses a value much greater than 1, the position of equilibrium lies toward the products. Kc is the ratio of product concentrations (raised to their stoichiometric powers) to reactant concentrations. If Kc ≫ 1, the numerator dominates, so at equilibrium you end up with much higher product concentrations than reactant concentrations. In other words, the system strongly favors the formation of products. Conversely, if Kc ≪ 1, reactants would be favored, and if Kc ≈ 1 there’s no strong preference.