Question

What is Catalyst? What is the effect of catalyst on the rate of reaction?

Answer 1

Catalyst:

• The substance that alters/changes the rate of reactions without itself being consumed is known as a catalyst.
• It is chemically unchanged at the end of the reaction.
• The mass of the catalyst is exactly the same as the initial mass when the reaction is finished.

Examples:

• Manganese dioxide $\left({\mathrm{MnO}}_2\right)$ is used in decomposition of Hydrogen peroxide $\left({\mathrm{H}}_2{\mathrm{O}}_2\right)$ and Potassium chlorate $\left({\mathrm{KClO}}_3\right)$.
• Sulfuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$ used in some esterification reactions.

Effect of catalyst on the rate of reaction:

• A positive catalyst increases the rate of reaction.
• A negative catalyst decreases the rate of reaction.
• The catalyst does not influence the amount of product formed.
• In the presence of a catalyst, an alternative pathway of reaction with lower activation energy is made available.
• More collisions of reactants are successful because less energy is required for success.
• After the reaction is over, the catalyst can be used again and again.