A-LevelChemistryElectrochemistryOct/Nov 2015Paper 1 Q71 Mark

The process of electrolysis can be used to purify copper, and to extract aluminium from an aluminium oxide/cryolite mixture. What are the reactions at the anode in each of these processes?

Q: What topic does this question test?

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

Apurification of copper: Cu2+ + 2e → Cu, extraction of aluminium: 2O2- → O2 + 4e-

Bpurification of copper: Cu2+ + 2e – Cu, extraction of aluminium: 4OH- → O2 + 2H2O + 4e¯

Cpurification of copper: Cu → Cu2+ + 2e-, extraction of aluminium: 2O2- → O2 + 4e-

Dpurification of copper: Cu → Cu2+ + 2e¯, extraction of aluminium: 4OH- → O2 + 2H2O + 4e¯

✓ Correct Answer

The correct answer is C: purification of copper: Cu → Cu2+ + 2e-, extraction of aluminium: 2O2- → O2 + 4e-

📋 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 2015 examination, Paper 1 Variant 2.

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