O-LevelChemistryRates of Reaction5070/11 · May/June 2022 · Q221 Mark

Nitrogen dioxide, NO2, is a dark brown gas that decomposes as shown in the equation. 2NO2(g) dark brown ⇌ 2NO(g) + O2(g) colourless The diagram shows a glass flask containing a mixture of the three gases. The mixture is pale brown. More oxygen is forced into the flask. Which colour change is seen in the mixture?

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.

AIt becomes a darker brown.

BIt becomes a paler brown.

CIt turns colourless.

DThere is no change.

✓ Correct answer

A: It becomes a darker brown.

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Topic: Rates of Reaction, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2022 Paper 1 Variant 1, question 22.

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