What are catalysts in chemical reactions?

A catalyst is a substance that speeds up the rate of a chemical reaction without being consumed or permanently changed in the process.

Key Points about Catalysts:

1. Function
   • Catalysts provide an alternative reaction pathway with a lower activation energy.
   • This allows more reactant particles to have enough energy to react, increasing the reaction rate.
2. Not Consumed
   • Unlike reactants, catalysts remain unchanged at the end of the reaction and can be reused.
3. Types of Catalysts
   • Homogeneous Catalyst: In the same phase as the reactants (e.g., H₂SO₄ in esterification).
   • Heterogeneous Catalyst: In a different phase from the reactants (e.g., solid Pt catalyst in hydrogenation of alkenes).
   • Enzymes: Biological catalysts that speed up reactions in living organisms (e.g., amylase breaking down starch).
4. Examples
   • Industrial: Iron catalyst in the Haber process (N₂ + H₂ → NH₃).
   • Daily Life: Catalytic converters in cars use Pt, Pd, and Rh to speed up the breakdown of harmful gases.
   • Biological: Catalase enzyme decomposes hydrogen peroxide (H₂O₂) into water and oxygen.