Question

For a reversible reaction where the substrate and product are in equilibrium, what will occur if an enzyme is added?

Answer 1

Answer: Nothing; the reaction will stay at equilibrium

There is no change in concentration at equilibrium because the rate of product formed is equal to the rate of product breakdown. When an enzyme is added, the rate of product formed and breaks will be increased. This will not shift the equilibrium because the rate of reaction is increased in both ways.