A-LevelChemistryElectrochemistryOct/Nov 2017Paper 1 Q331 Mark

Hydrogen sulfide can be oxidised to form sulfur dioxide. 2H2S + 3O2 → 2SO2 + 2H2O Which statements are correct? 1 The oxidation number of sulfur increases by 6. 2 The oxidation number of oxygen increases by 2. 3 The oxidation number of hydrogen decreases.

Q: What is the correct answer to this A-Level Chemistry question?

The correct answer is D: 1 only is correct.

Q: What topic does this question test?

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

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 Electrochemistry in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Oct/Nov 2017 examination, Paper 1 Variant 2.

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