What is a catalyst? Give one example

Hint: To answer this question, you should recall the concept of catalysts. It can be defined as a substance that changes the reaction rate by changing the path of reaction. It does not affect the equilibrium of the reaction.

Complete step by step answer:
Catalyst is a very usual word that comes up in the topic of chemical reactions. Generally, a catalyst speeds up and increases the reaction rate. Catalysts break or rebuild the chemical bonds between the atoms which are present in the molecules of different elements or compounds. Catalysts make the whole reaction process easier and efficient.

Key points of a catalyst are:
-It does not initiate a chemical reaction.
-It cannot be consumed in the reaction.
-It forms intermediates with reactants and at the same time facilitates the production of the final reaction product.
-An example of a catalyst is potassium permanganate in the decomposition of Hydrogen peroxide in water and oxygen gas. Potassium permanganate acts as a catalyst leading to the increased speed of reaction. It produces a lot of heat and the water is removed as vapour.

Note:
There are four types of catalysts:
1. Positive Catalysts: Catalysts which increase the rate of a chemical reaction are positive catalysts. It increases the rate of reaction by lowering the activation energy barriers such that a large number of reaction molecules are converted into products, thereby the percentage of yield of products increases.
2. Negative Catalysts: Catalysts which decrease the rate of reaction and negative catalyst.
3. Promoter or Accelerators: A substance which increases the catalyst activity are known as Promoters or accelerators.
4. Catalyst Poisons or Inhibitors: Substances which decrease the catalyst activity are known as catalyst poisons or inhibitors.