A-LevelChemistryGroup 29701/12 · Feb/Mar 2025 · Q211 Mark

River water in an agricultural area contains NH4⁺, CO3²⁻, HCO3⁻, Cl⁻ and NO3⁻ ions. This water is treated by adding a calculated quantity of calcium hydroxide. What is precipitated from the river water when calcium hydroxide is added?

ACaCl2

BCaCO3

CCa(NO3)2

DNH4OH

✓ Correct answer

B: CaCO3

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