Chemistry · May / June 2023 · Paper 12 · Question 23

The addition of calcium hydroxide to soil reduces its acidity but also reduces the efficiency of fertilisers. Which two equations explain this? 1 Ca(OH)2(s) + CO2(g) → CaCO3(s) + H2O(l) 2 Ca(OH)2(s) + 2H+(aq) → Ca2+(aq) + 2H2O(l) 3 Ca(OH)2(s) + 2NH4NO3(aq) → Ca(NO3)2(aq) + 2NH3(g) + 2H2O(l) 4 Ca(OH)2(s) + Cu2+(aq) → Cu(OH)2(s) + Ca2+(aq)

1. A1 and 2
2. B1 and 4
3. C2 and 3
4. D3 and 4

As printed in the paper