Question

Regarding the criteria of catalysis, which one of the following statements is not true?
A. The catalyst is unchanged chemically during the reaction.
B. A small quantity of catalyst is often sufficient to bring about a considerable amount of the reaction.
C. In a reversible reaction, the catalyst alters the equilibrium position.
D. The catalyst accelerates the rate of reaction.

Answer 1

Hint: Catalyst is a chemical species that is utilised to speed up the rate of a reaction by not having a modification in its quantity or chemical arrangement when the reaction stops. This process of a surge in the rate of a reaction when a catalyst is added is called catalysis.

Complete Step by Step Answer:
The rate of a reaction normally rises when a catalyst is added.
We have to find out which of the given options is not true in the case of catalysts.
A. The catalyst is unaffected chemically during the reaction.
The catalyst stays unaffected in terms of amount and chemical arrangement after the culmination of a reaction.
So, A is true so it is incorrect.
B. A small quantity of catalyst is often sufficient to bring about a considerable amount of the reaction.
Simply a slight amount of a catalyst is needed
which catalyses a reaction.
This small amount of catalyst is apt to bring a considerable number of reactants to constitute products in less time.
So, B is incorrect as B is true.
C. In a reversible reaction, the catalyst changes the equilibrium position.
Catalysts do not affect or change the position of equilibrium in a reaction. It influences forward and backward reactions in the same manner hence it doesn't alter the equilibrium position.
The equilibrium of a reaction stays unchanged if the catalyst is present.
So, C is not true so it is correct.
D. The catalyst speeds up the rate of reaction.
The catalyst only speeds up the rate of the reaction. The reaction when a catalyst is present happens through the reaction pathway which requires lower activation energy.
So, D is true so it is incorrect.
So, option C is correct.

Note: We should observe that catalysts, in a reversible reaction, do not alter the equilibrium position. It accelerates the rate of reaction, remains unchanged chemically, and a small amount of it is enough to bring about a reaction.