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Which compound decolorises acidified potassium manganate(VII) solution? A - AQA - A-Level Chemistry - Question 21 - 2020 - Paper 3
Question 21
Which compound decolorises acidified potassium manganate(VII) solution? A. Al(SO₄)₃ B. CuSO₄ C. FeSO₄ D. Fe₂(SO₄)₃
Worked Solution & Example Answer:Which compound decolorises acidified potassium manganate(VII) solution? A - AQA - A-Level Chemistry - Question 21 - 2020 - Paper 3
Step 1
Identify the compound that reduces potassium manganate(VII):
Answer
The correct answer is C: FeSO₄.
When acidified potassium manganate(VII) solution is added to FeSO₄, the Fe²⁺ ions present reduce the MnO₄⁻ ions in the solution to Mn²⁺ ions, causing the purple color of the solution to disappear.