A catalyst

• A. Speeds up the reaction and is consumed
• B. Speeds up the reaction without being consumed
• C. Changes the equilibrium constant
• D. Is always a product

Answer: (B)

A catalyst works by providing an alternative reaction pathway with a lower activation energy, which lets the reaction proceed faster without using up the catalyst itself. Because it’s regenerated at the end of the process, the amount of catalyst stays the same, so it can keep speeding up subsequent reactions. This also means the equilibrium between reactants and products isn’t shifted—the catalyst increases both forward and reverse rates equally, so the position of equilibrium (the constant) remains unchanged. Catalysts aren’t typically products; they’re present before and after the reaction, guiding the process but not being consumed.