What is the role of a catalyst in a chemical reaction?

A catalyst speeds up a chemical reaction without being consumed or altered in the process.

In more detail, a catalyst is a substance that can increase the rate of a chemical reaction by providing an alternative reaction pathway with a lower activation energy. Activation energy is the minimum energy required for a reaction to occur. By lowering this energy barrier, a catalyst allows more reactant particles to have enough energy to react, thus speeding up the reaction.

Catalysts are not consumed in the reaction, meaning they can be used repeatedly. They do not appear in the overall balanced chemical equation for the reaction because they do not change or become part of the products. However, they may temporarily bond with reactants during the reaction process, forming an intermediate compound that quickly breaks down to release the products and regenerate the catalyst.

Catalysts can be either homogeneous or heterogeneous. Homogeneous catalysts are in the same phase (solid, liquid, or gas) as the reactants, while heterogeneous catalysts are in a different phase. An example of a homogeneous catalyst is the use of sulfuric acid in the production of esters from carboxylic acids and alcohols. A common example of a heterogeneous catalyst is the use of finely divided platinum in catalytic converters in cars to speed up the breakdown of harmful gases into less harmful substances.

Understanding the role of catalysts is crucial in many areas of chemistry and industry. They are used extensively in industrial processes to increase the efficiency and speed of reactions, reducing costs and environmental impact. For example, in the Haber process for the production of ammonia, an iron catalyst is used to speed up the reaction between nitrogen and hydrogen.