№1
1. 2Ca + O₂ = 2CaO
2. CaO + H₂O = Ca(OH)₂
3. 3Ca(OH)₂ + 2H₃PO₄ = Ca₃(PO₄)₂ + 6H₂O
4. Ca + 2HCl = CaCl₂ + H₂↑
№2
1. 2Na + 2H₂O = 2NaOH + H₂↑
2. 2NaOH + H₂CO₃ = Na₂CO₃ + 2H₂O
3. Na₂CO₃ = (t) Na₂O + CO₂↑
4. CaO + CO₂ = CaCO₃
№3
1. 4P + 5O₂ = 2P₂O₅
2. P₂O₅ + 3H₂O = 2H₃PO₄