Each of the questions or incomplete statements below is followed by five suggested answers or completions. Select the one that is best in each case.
Which of the following statements about catalysts is true?
Select an Answer
They increase the value of the equilibrium constant.
They increase the amount of product present at equilibrium.
They increase the concentration of the reactants.
They are permanently altered as the reaction proceeds.
They reduce the activation energy of the reaction.
Catalysts work by providing a new pathway with a lower activation energy for the reaction. Catalysts have no effect on the value of the equilibrium constant, so (A) is not true. If the equilibrium constant does not change then the amounts and concentrations of the reactants and products at equilibrium do not change, so (B) and (C) are not true. A catalyst speeds up a reaction but it is not permanently altered or consumed in the reaction, so (D) is not true.