Question

Which of the following statements is not correct for the catalyst?
A. it catalyses the forward and backward reaction to the same extent.
B. it alters $\Delta G$ of the reaction.
C. it is a substance that does not change the equilibrium constant of a reaction.
D. if provides an alternate mechanism by reducing activation energy between reactants and
products.

Answer 1

Catalyst is a common word that you might come across while studying chemistry especially while learning about chemical reactions. While some of the chemical reactions occur quickly, some take a long time and require extra materials or effort. So, catalysts are defined as those substances which alter the rate of reaction by changing the path of reaction.

Complete answer:
A catalyst can be either solid, liquid or gaseous catalyst. A catalyst increases reaction rates in a slightly different way from other methods of increasing reaction rate. The function of a catalyst is to lower the activation energy so that a greater proportion of the particles have enough energy to react.
Types of Catalysts are:

1. Positive Catalysts : Catalysts which increase the rate of a chemical reaction are positive catalysts.
2. Negative Catalysts: Catalysts which decrease the rate of reaction and negative catalyst.
   The function of a catalyst is to lower the activation energy so that a greater proportion of the particles have enough energy to react.
   A catalyst increases the rate of reaction by decreasing the activation energy of the reaction. It does not affect the Gibbs free energy $\Delta G$ of the reaction.

Thus, the statement given in option (B) is incorrect.

Note: In essence, catalysts encourage molecules to react and make the whole reaction process easier and efficient.