A-LevelChemistryReaction kineticsFeb/Mar 2022Paper 1 Q111 Mark

Hydrogen peroxide, H₂O₂, decomposes to form water and oxygen. The reaction is catalysed by bromide ions. step 1 2Br⁻(aq) + H₂O₂(aq) + 2H⁺(aq) → 2H₂O(l) + Br₂(aq) step 2 H₂O₂(aq) + Br₂(aq) → 2Br⁻(aq) + 2H⁺(aq) + O₂(g) Which row is correct? [Figure 11.1]

Q: What topic does this question test?

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

Aheterogeneous, bromide ions are oxidised

Bheterogeneous, bromide ions are reduced

Chomogeneous, bromide ions are oxidised

Dhomogeneous, bromide ions are reduced

✓ Correct Answer

The correct answer is C: homogeneous, bromide ions are oxidised

📋 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 Feb/Mar 2022 examination, Paper 1 Variant 2.

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