2) Na₂O + H₂O = 2NaOH
NaOH + NH₄NO₃ = NaNO₃ + NH₄OH (разлагается на NH₃ + H₂O)
NH₄OH ⇔ NH₃ + H₂O
3) CuO + 2HNO₃ = Cu(NO₃)₂ + H₂O
Cu(NO₃)₂ + 2KOH = Cu(OH)₂↓ + 2KNO₃
Cu(OH)₂ = CuO + H₂O
4) Na₂O + CO₂ = Na₂CO₃
Na₂CO₃ + CaCl₂ = 2NaCl + CaCO₃↓
NaCl + AgNO₃ = NaNO₃ + AgCl↓
2NaNO₃ = 2NaNO₂ + O₂↑