Answer:Catalyst
Step-by-step explanation:
Catalyst is a compound that increases the rate of chemical reaction without itself being consumed or altered. It can be recovered chemically at the end of reaction.
It may be classified as,
-Homogeneous catalyst :in which the reaction mixture and the catalyst are in the same . This type of catalyst is used in oxidation
- Heterogeneous catalyst : in which the reaction mixture and the catalyst are in different phase. This type is used is Haber-Bosch process.