O-LevelChemistryAcids, Bases & Salts5070/11 · May/June 2022 · Q31 Mark

Two samples of a colourless solution are tested separately with aqueous sodium hydroxide, NaOH(aq), and aqueous ammonia, NH3(aq), and the results are recorded. • A white precipitate is formed with two drops of NaOH(aq). This precipitate dissolves in an excess of NaOH(aq). • A white precipitate is formed with two drops of NH3(aq). This precipitate dissolves in an excess of NH3(aq). What can be deduced from these results?

AThe anion present is Cl¯.

BThe anion present is not Cl¯.

CThe cation present is Al³⁺.

DThe cation present is Zn²⁺.

✓ Correct answer

D: The cation present is Zn²⁺.

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Topic: Acids, Bases & Salts, O-Level Chemistry (syllabus 5070). Multiple choice, 1 mark.
Source: O-Level Chemistry, May/June 2022 Paper 1 Variant 1, question 3.

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