O-LevelChemistryAcids, Bases & Salts5070/11 · May/June 2021 · Q41 Mark

J is an aqueous solution. On addition of aqueous sodium hydroxide to J a green precipitate is formed. The resulting mixture is heated and no gas is formed. Aluminium foil is added to the warmed mixture. A gas is formed that turns damp red litmus paper blue. Which ions could be present in J?

AFe³⁺ and NH₄⁺

BFe³⁺ and NO₃⁻

CFe²⁺ and NH₄⁺

DFe²⁺ and NO₃⁻

✓ Correct answer

D: Fe²⁺ and NO₃⁻

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Topic: Acids, Bases & Salts, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2021 Paper 1 Variant 1, question 4.

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