A catalyst increases the rate of a reaction by:

A catalyst increases the rate of a reaction by:

• A. Increasing temperature
• B. Providing an alternative pathway with lower activation energy
• C. Increasing reactant concentration
• D. Reducing product formation

Answer: (B)

Catalysts speed up reactions by providing an alternative pathway with a lower activation energy. This means the energy barrier that must be overcome for reactants to transform into products is smaller, so a larger fraction of molecules can react in a given time at the same temperature. Because the catalyst is not consumed and does not change the overall energy change of the reaction, it increases the rate without altering the final amount of products formed. The other ideas describe different ways to influence rate, but not how a catalyst works: increasing temperature raises kinetic energy and speeds up reactions, but that’s not the catalyst’s action; increasing reactant concentration increases collision frequency, again not the catalytic mechanism; reducing product formation would affect the outcome or balance, not provide a faster pathway.

Catalysts speed up reactions by providing an alternative pathway with a lower activation energy. This means the energy barrier that must be overcome for reactants to transform into products is smaller, so a larger fraction of molecules can react in a given time at the same temperature. Because the catalyst is not consumed and does not change the overall energy change of the reaction, it increases the rate without altering the final amount of products formed.

The other ideas describe different ways to influence rate, but not how a catalyst works: increasing temperature raises kinetic energy and speeds up reactions, but that’s not the catalyst’s action; increasing reactant concentration increases collision frequency, again not the catalytic mechanism; reducing product formation would affect the outcome or balance, not provide a faster pathway.