Chemistry – Chemical reactions - Rate of reaction | e-Consult

Effect of a Catalyst: Adding a catalyst generally increases the rate of reaction. Removing a catalyst generally decreases the rate of reaction.

Explanation: A catalyst is a substance that speeds up a chemical reaction without being consumed in the process. Catalysts work by providing an alternative reaction pathway with a lower activation energy. This means that a larger proportion of the reactant particles will have sufficient energy to react, leading to a faster rate of reaction.

Enzymes as Catalysts: Enzymes are biological catalysts, typically proteins, that are highly specific for their substrates. They bind to the substrate at an active site, forming an enzyme-substrate complex. This complex lowers the activation energy of the reaction, accelerating the rate. Enzymes can be denatured by heat, pH changes, or other factors, which can remove their catalytic activity and slow down or stop the reaction. The effect of removing an enzyme is a decrease in the rate of reaction, as the reaction pathway with the lower activation energy is no longer available.