Question

Account for the increase in reaction rate brought about by a catalyst.

Short answer

Catalysts increases the rate of the reaction by decreasing the activation energy, by involving another reaction mechanism by allowing the reaction to attain equilibrium faster.

Step-by-step solution

Definition of catalyst

Catalyst are substances which increases the rate of the reaction without getting used up by themselves while decreasing the activation energy of the reaction.

Increase in the Reaction rate bought by a catalyst

• Catalysts increase the rate of reaction by decreasing the activation energy. Example: Catalytic hydrogenation (alkene hydrogenation).

• Many reactions occur at thermodynamically favourable conditions, but in the presence of catalyst, reactions occur at reasonable rate.

• As the catalyst decrease the activation energy, it increases both forward and reverse reaction and makes reaction to attain equilibrium very fast.

• The below graph represents the catalyzed and uncatalyzed alkene hydrogenation.

Thus, catalysts increase the rate of the reaction without taking part in the reaction and allows the reaction to attain equilibrium quickly.