Carbon dioxide (CO₂) as a gas — select the correct set of properties relevant to fire and safety considerations.
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Acolourless
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Bodourless
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Cnon-flammable
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Dall of these
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Etoxic and highly flammable
Answer
Correct Answer: all of these
Explanation
Introduction / Context:Basic gas properties are essential in refrigeration, fire suppression, and safety engineering. CO₂ is widely used as a fire extinguishing agent and as a refrigerant in transcritical systems.
Given Data / Assumptions:
- CO₂ at ordinary conditions (non-cryogenic).
- Properties considered: colour, odour, and flammability.
Concept / Approach:CO₂ is colourless and odourless. It does not support combustion and is used to smother fires by diluting oxygen concentration. While CO₂ is asphyxiant at high concentrations, it is not classified as a flammable gas.
Step-by-Step Solution:
Check colour: CO₂ is colourless.Check odour: CO₂ is odourless.Check flammability: CO₂ is non-flammable and used in extinguishers.Therefore, “all of these” is correct.Verification / Alternative check:Fire codes and data sheets list CO₂ as non-flammable and suitable for certain classes of fires, confirming these properties.
Why Other Options Are Wrong:
Picking any single property ignores the others; “toxic and highly flammable” is incorrect.
Common Pitfalls:Confusing CO₂ with CO (carbon monoxide). CO is toxic; CO₂ is an asphyxiant at high concentrations but not flammable.
Final Answer:
all of these