Chemistry 2008 JAMB Past Questions - Question 28: A catalyst speeds up the rate of a chemical reaction by

Correct Answer

C

Explanation

A catalyst speeds up the rate of a chemical reaction by **lowering the activation energy** required for the reaction to occur. Here's a breakdown of how it works:

**Imagine a mountain range representing the energy barrier for a chemical reaction.**

* **Without a catalyst:** Most reactant molecules don't have enough energy to overcome the initial high peak (activation energy) and reach the other side (products). Only a small fraction with high energy can cross the peak, making the reaction slow.
* **With a catalyst:** The catalyst acts like a **shortcut or tunnel** through the mountain range. This lowers the activation energy needed for the reaction to occur, allowing more reactant molecules to cross the peak and reach the products. Consequently, the reaction becomes **faster**.

Here are some additional details about how catalysts work:

* **Catalysts don't change the overall energy of the reaction.** They just provide an alternative pathway with lower activation energy.
* **Catalysts remain unchanged** after the reaction and can be reused.
* **Different catalysts** can be specific to certain reactions and can even influence the selectivity of the reaction, favoring the formation of desired products.