A-LevelChemistryCarboxylic acids and derivativesFeb/Mar 2020Paper 1 Q221 Mark

The diagram shows the structure of ethanedioic acid. [Figure 22.1] Ethanedioic acid reacts with ethanol in the presence of a few drops of concentrated sulfuric acid to form a diester. The molecular formula of the diester is C6H10O4. What is the structural formula of the diester?

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

The correct answer is B: CH3CH2OCOCO2CH2CH3.

Q: What topic does this question test?

This question tests Carboxylic acids and derivatives in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

ACH3CH2CO2CO2CH2CH3

BCH3CH2OCOCO2CH2CH3

CCH3CH2O2CO2CCH2CH3

DCH3CO2CH2CH2OCOCH3

✓ Correct Answer

The correct answer is B: CH3CH2OCOCO2CH2CH3

📋 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 Carboxylic acids and derivatives in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry Feb/Mar 2020 examination, Paper 1 Variant 2.

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