A-LevelChemistryElectrochemistryOct/Nov 2013Paper 1 Q31 Mark

The following half reactions occur when potassium iodate(V), KIO3, in hydrochloric acid solution oxidises iodine to ICl2⁻. IO3⁻ + 2Cl⁻ + 6H⁺ + 4e⁻ → ICl2⁻ + 3H2O I2 + 4Cl⁻ → 2ICl2⁻ + 2e⁻ What is the ratio of IO3⁻ to I2 in the balanced chemical equation for the overall reaction?

Q: What topic does this question test?

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

A1:1

B1:2

C1:4

D2:1

✓ Correct Answer

The correct answer is B: 1:2

📋 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.

🔒

Unlock the Examiner's Analysis

Join thousands of Cambridge students already using Oracle Prep

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 2013 examination, Paper 1 Variant 2.

Practice on Oracle Prep

Oracle Prep provides AI-powered practice for all Cambridge O-Level and A-Level subjects. Our platform includes topic predictions with 87.7% accuracy, AI essay grading, and a comprehensive question bank spanning 25 years of past papers across 29 subjects.