A-LevelChemistryGroup 2Oct/Nov 2015Paper 1 Q51 Mark

Calcium forms an ionic compound with carbon, called calcium carbide. The oxidation number of carbon in calcium carbide is –1. Calcium carbide is readily hydrolysed by water giving two products only. What could be the formulae of calcium carbide and the two products of hydrolysis?

Q: What topic does this question test?

This question tests Group 2 in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Acalcium carbide: Ca2C, products: CaO and C2H4

Bcalcium carbide: Ca2C, products: Ca(OH)2 and C2H2

Ccalcium carbide: CaC2, products: CaO and C2H4

Dcalcium carbide: CaC2, products: Ca(OH)2 and C2H2

✓ Correct Answer

The correct answer is D: calcium carbide: CaC2, products: Ca(OH)2 and C2H2

📋 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 Group 2 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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