Hello Aspirant

A catalyst is a compound that make the rate of reaction faster without itself being involved in the reaction.

It remains unchanged in mass and chemical composition at the end of the reaction.

The catalyst is required in generally very small quantities as it remains almost unreacted at the end of the reaction and therefore we don't need to add it again and again

Hello ,

Catalyst : It is a substance that can alter the rate of a reaction without being consumed in the reaction.

Characteristics of a catalyst are as follows :

• Catalyst may undergo physical changes but not chemical
• Small quantities of catalyst are sufficient for catalysis.
• Catalyst activates the rate of reaction but cannot initiate it
• Catalytic activity is maximum at optimum temperature
• Catalyst lowers the activation energy of forward and backward reaction and also lowers threshold energy
• It provides a new mechanism for the reaction
• It does not change the energy and extent of reaction

Hope this helps