Which statement about catalysts is true?

• A. They speed up the rate of reaction by lowering activation energy
• B. They are used up in the reaction
• C. They affect the chemical equilibrium
• D. Two of the above

Answer: (A)

Catalysts work by providing an alternative pathway with a lower activation energy, the energy barrier that reactants must overcome to convert into products. By lowering this barrier, more molecules have enough energy to react at a given temperature, so the reaction rate increases. They are not consumed in the reaction, and they speed up both forward and reverse reactions equally, so the position of equilibrium remains unchanged. They do not change how much product is formed at equilibrium; they only make it reach that point faster. That’s why the statement describing catalysts as speeding up the rate by lowering activation energy is the true one.