A-LevelChemistryGroup 2Oct/Nov 2011Paper 1 Q181 Mark

Lime mortar is made from quicklime, water and sand. Over a period of time, lime mortar changes into a much harder form. Both fresh and old lime mortar react with aqueous hydrochloric acid but only the old lime mortar effervesces during the reaction. Which equation describes the change from fresh to old lime mortar?

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

The correct answer is D: Ca(OH)2 + CO2 → CaCO3 + H2O.

Q: What topic does this question test?

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

ACaO + CO2 → CaCO3

BCaO + H2O → Ca(OH)2

CCa(OH)2 → CaO + H2O

DCa(OH)2 + CO2 → CaCO3 + H2O

✓ Correct Answer

The correct answer is D: Ca(OH)2 + CO2 → CaCO3 + H2O

📋 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 2011 examination, Paper 1 Variant 2.

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