A-LevelChemistryAtoms, molecules and stoichiometryMay/June 2025Paper 1 Q51 Mark

'Red lead' is a red pigment with the formula Pb3O4. Every formula unit of 'red lead' is the same. Each formula unit contains three lead ions and four oxide ions. Lead has two different oxidation states in 'red lead'. What are the oxidation states of lead in 'red lead'?

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

The correct answer is C: +2 and +4.

Q: What topic does this question test?

This question tests Atoms, molecules and stoichiometry in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

A+1 and +2

B+1 and +3

C+2 and +4

D+2 and +6

✓ Correct Answer

The correct answer is C: +2 and +4

📋 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 Atoms, molecules and stoichiometry in A-Level Chemistry (syllabus code 9701). It is worth 1 mark.

Source

This question appeared in the Cambridge A-Level Chemistry May/June 2025 examination, Paper 1 Variant 2.

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