How does a catalyst affect activation energy and reaction rate?

• A. It lowers activation energy and increases reaction rate without being consumed.
• B. It raises activation energy and slows the reaction.
• C. It has no effect on activation energy or rate.
• D. It is consumed in the reaction.

Answer: (A)

A catalyst works by providing an alternative reaction pathway with a lower activation energy, so more particles have enough energy to react at the same temperature. Lowering this energy barrier means the same number of collisions now has the energy to proceed, so the reaction rate increases. A catalyst is not consumed in the process; it can be reused to catalyze more reactions. The overall energy change of the reaction stays the same—the catalysts don’t alter the amount of energy released or absorbed—just how quickly the reaction occurs. So this statement accurately describes how catalysts affect activation energy and rate.