Which of the following is an example of heterogeneous catalysis ?

Options

A. `n(CH_(2)=CH_(2))overset(R_(3)Al+TiCl_(4))rarr [-CH_(2)-CH_(2)-]_(4)`
B. `2SO_(2)+O_(2)overset("Pt - Asbestos")rarr2SO_(3)`
C. `RCOORoverset(H^(+))underset("Catalyst")rarrRCOOH+ROH`
D. `2H_(2)O_(2)(l)overset(Hg(l))rarr 2H_(2)O+O_(2)`

Answer

To determine which of the following options represents an example of heterogeneous catalysis, we need to understand the definition of heterogeneous catalysis. Heterogeneous catalysis occurs when the catalyst is in a different phase (solid, liquid, or gas) than the reactants and products involved in the reaction.

Let's analyze the options step by step:

1. **Identify the phases of the reactants and catalyst**:
- We need to look at each option and identify the physical states (solid, liquid, gas) of the catalyst and the reactants/products.

2. **Evaluate the options**:
- **Option 1**: If the catalyst and the reactants/products are in the same phase (e.g., all gases or all liquids), this is not heterogeneous catalysis.
- **Option 2**: If the catalyst is in a different phase from the reactants/products, this indicates heterogeneous catalysis. For example, if the catalyst is a solid and the reactants/products are gases, this is a classic example of heterogeneous catalysis.
- **Option 3**: Similar to option 1, if the catalyst and the reactants/products are in the same phase, it is not heterogeneous catalysis.

3. **Conclusion**:
- After analyzing the options, we find that **Option 2** is the correct answer. In this case, sulfur dioxide (SO2) and oxygen (O2) are gases, while the catalyst (platinum) is a solid, which confirms that this is an example of heterogeneous catalysis.

### Final Answer:
The correct example of heterogeneous catalysis is **Option 2**.