| Aspect | Heterogeneous Catalyst | Homogeneous Catalyst |
|---|---|---|
| Phase | Different phase (e.g., solid catalyst, gas/liquid reactants) | Same phase (e.g., liquid/liquid or gas/gas) |
| Mechanism | Surface-bound: adsorption, reaction, desorption | Uniform: reaction occurs throughout the medium |
| Separation | Simple (filtration/centrifugation) | Complex (requires distillation/extraction) |
| Efficiency | Depends on active surface area | Depends on molecular interaction/solubility |
| Examples | Iron (Haber Process); V2O5 (Contact Process) | Enzymes (Biochemical); H+ ions (Esterification) |
Key takeaway: Heterogeneous catalysis relies on interfaces (active sites on a surface), whereas homogeneous catalysis relies on the uniform distribution of reactants and catalysts within a single phase.
Test Your Knowledge: Heterogeneous and Homogeneous Catalysts
Q1. Which of the following statements correctly describes a heterogeneous catalyst?
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Correct Answer: B. Catalyst and reactants are in different phases
Explanation: A heterogeneous catalyst exists in a different phase from the reactants, usually solid while the reactants are gases or liquids. The reaction occurs on the catalyst’s surface through adsorption and desorption steps.
Q2. Which of the following is an example of a homogeneous catalytic reaction?
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Correct Answer: C. Esterification using concentrated sulfuric acid
Explanation: In esterification, both the reactants (acid and alcohol) and the catalyst (H2SO4) are in the liquid phase, making it a homogeneous catalytic reaction.
Q3. What is the main advantage of using a heterogeneous catalyst over a homogeneous one?
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Correct Answer: B. Easier separation from products
Explanation: Heterogeneous catalysts are in a different phase (often solid), so they can be easily separated from the reaction products by filtration or decantation, unlike homogeneous catalysts which remain mixed in the same phase.
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