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A-LevelChemistryReaction kineticsMay/June 2013Paper 1 Q361 Mark

Sulfur dioxide is an atmospheric pollutant that causes acid rain. One of the reactions in this process is the oxidation of sulfur dioxide to sulfur trioxide. This oxidation takes place by a two stage reaction involving oxygen and nitrogen monoxide, NO. NO + ½ O₂ → NO₂ NO₂ + SO₂ → SO₃ + NO Which statements are correct? 1 Nitrogen monoxide is acting as a catalyst for the oxidation. 2 Nitrogen atoms are oxidised in the second stage. 3 Oxygen atoms are first reduced and are then oxidised.

A1, 2 and 3 are correct
B1 and 2 only are correct
C2 and 3 only are correct
D1 only is correct

✓ Correct Answer

The correct answer is D: 1 only is correct

📋 Examiner Report & Trap Analysis

Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...

🎯 Mark Scheme Breakdown

Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.

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About This A-Level Chemistry Question

Topic

This multiple-choice question tests Reaction kinetics in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry May/June 2013 examination, Paper 1 Variant 2.

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