Question

what is the effect of catalyst on the rate of reaction

Answer 1

It increase the rate of reaction.

Answer 2

Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst, which is not consumed in the catalyzed reaction and can continue to act repeatedly. Often only tiny amounts of catalyst are required in principle.In general, reactions occur faster with a catalyst because they require less activation energy.
Thus catalyst helps in speeding up the reaction which is called positive catalyst. Negative catalyst decreases speed of reaction
Hope I helped!