Which statement about catalysts and equilibrium is true?

Which statement about catalysts and equilibrium is true?

• A. They shift the equilibrium toward products
• B. They do not shift the equilibrium; they speed up the rate
• C. They change the energy difference between reactants and products
• D. They are consumed in the reaction

Answer: (B)

Catalysts affect how fast a reaction reaches equilibrium, not where the equilibrium lies. They provide an alternative pathway with lower activation energy for both forward and reverse directions, so both rates increase. Because the ratio of products to reactants at equilibrium (the equilibrium constant) is set by thermodynamics, not by the speed of the reaction, the equilibrium position stays the same even though the system reaches it faster. Catalysts are not consumed and do not change the energy difference between reactants and products, so ΔG° for the reaction at a given temperature remains unchanged.

Catalysts affect how fast a reaction reaches equilibrium, not where the equilibrium lies. They provide an alternative pathway with lower activation energy for both forward and reverse directions, so both rates increase. Because the ratio of products to reactants at equilibrium (the equilibrium constant) is set by thermodynamics, not by the speed of the reaction, the equilibrium position stays the same even though the system reaches it faster. Catalysts are not consumed and do not change the energy difference between reactants and products, so ΔG° for the reaction at a given temperature remains unchanged.