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CAIE IGCSE Chemistry Potassium Manganate and Iodide Redox Tests

CAIE IGCSE Chemistry Potassium Manganate and Iodide Redox Tests
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise using acidified potassium manganate(VII) and potassium iodide colour changes to identify reducing or oxidising substances in redox tests.

How this is tested

  • identify a reducing agent when acidified manganate(VII) changes from purple to colourless
  • identify an oxidising agent when iodide solution changes from colourless to brown iodine
  • state the acidic condition for the manganate(VII) test and report both start and end colours

Question 5(d)(ii)

[Maximum number: 2]

Sulfur is a Group VI element.

Na2SO3\mathrm{Na}_{2} \mathrm{SO}_{3} is oxidised by acidified aqueous potassium manganate(VII).

State the colour change when this reaction happens.
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