O-LevelChemistryChemistry of the Environment5070/12 · May/June 2019 · Q311 Mark

Which statement about some of the gases present in air is correct?

ADry air contains about 78% of oxygen.

BMethane is produced by the incomplete combustion of fossil fuels.

CSulfur dioxide is released by volcanoes.

DThe noble gases make up about 5% of dry air.

✓ Correct answer

C: Sulfur dioxide is released by volcanoes.

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Topic: Chemistry of the Environment, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2019 Paper 1 Variant 2, question 31.

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