Chemistrymedium · Past Paper
In the laboratory preparation of carbon dioxide, why is it collected by upward displacement of air?
AIt is lighter than air
BIt is heavier than air
CIt is insoluble in water
DIt reacts with water
✓ Correct Answer: B — It is heavier than air
Carbon dioxide has a molar mass of 44 g/mol compared to the average 29 g/mol for air, making it denser and allowing it to displace air upwards.
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