O-LevelChemistryRates of Reaction5070/12 · May/June 2021 · Q211 Mark

Brown nitrogen dioxide reacts to form colourless dinitrogen tetroxide in a reversible reaction. The forward reaction is exothermic. 2NO2(g) ⇌ N2O4(g) brown colourless Which changes would make the equilibrium mixture darker in colour?

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Atemperature: decrease, pressure: decrease

Btemperature: decrease, pressure: increase

Ctemperature: increase, pressure: decrease

Dtemperature: increase, pressure: increase

✓ Correct answer

C: temperature: increase, pressure: decrease

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2021 Paper 1 Variant 2, question 21.

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