Write brief notes on the following: (ii) Heterogeneous catalysis

Answer

### Step-by-Step Text Solution:

1. **Definition of Heterogeneous Catalysis**:
Heterogeneous catalysis occurs when the catalyst is in a different phase than the reactants and products involved in the chemical reaction. This means that if the reactants are in a liquid phase, the catalyst may be in a solid phase, or if the reactants are gases, the catalyst may be a solid.

2. **Characteristics**:
- The catalyst is not consumed in the reaction and can be recovered and reused.
- The reaction typically occurs at the surface of the catalyst, where the reactants adsorb onto the catalyst surface, facilitating the reaction.

3. **Example**:
A common example of heterogeneous catalysis is the hydrogenation of vegetable oils. In this process, vegetable oil (liquid) reacts with hydrogen gas (gaseous) in the presence of a solid catalyst, such as powdered nickel (Ni). The nickel facilitates the reaction, leading to the formation of solid fats.

4. **Importance**:
Heterogeneous catalysis is widely used in industrial processes, including the production of chemicals, fuels, and pharmaceuticals, due to its efficiency and the ability to easily separate the catalyst from the products.