AQA A-Level Chemistry Paper 3, 2023: Question 27
1 mark · Medium difficulty · Multiple Choice
Processes and Catalysts This question tests understanding of industrial and natural chemical processes, specifically identifying which process does not utilise a heterogeneous catalyst.
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Question text
27 Which process does not involve a heterogeneous catalyst?
[1 mark]
A catalytic cracking of alkanes
B Contact process
C decomposition of ozone
D Haber process
Mark scheme
Show the mark scheme
27 C 1 (AO1) decomposition of ozone
How to answer it
Heterogeneous and Homogeneous Catalysis
Question
Which process does not involve a heterogeneous catalyst?
- A: Catalytic cracking of alkanes
- B: Contact process
- C: Decomposition of ozone
- D: Haber process
Correct Answer: C
The correct answer is C: Decomposition of ozone . This process involves a homogeneous catalyst, such as chlorine radicals, which exist in the same phase as the reactants (gaseous ozone molecules).
Explanation of Other Options
- A: Catalytic cracking of alkanes uses a heterogeneous catalyst, typically a solid zeolite.
- B: The Contact process employs vanadium(V) oxide ( V2O5 ), a solid catalyst, making it heterogeneous.
- D: The Haber process involves a solid iron catalyst, which is another example of heterogeneous catalysis.
Key Concepts
Heterogeneous Catalysis: The catalyst is in a different phase than the reactants. Examples include the Haber process and the Contact process.
Homogeneous Catalysis: The catalyst and reactants are in the same phase, as seen in the decomposition of ozone catalysed by chlorine radicals.
Final Answer
The correct choice is:
C: Decomposition of ozone
Topics
Inorganic Chemistry · 3.2.5 Transition Metals
Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.