Ответ:
а) P - P₂O₅ - H₃PO₄ - Ca₃(PO₄)₂
4P+5O₂= 2P₂O₅
P₂O₅ +3H₂O= 2H₃PO₄
2H₃PO₄ +3Ca(OH)₂= Ca₃(PO₄)₂+6H₂O
6H⁺+2PO₄³⁻ +3Ca²⁺+6OH⁻= 3Ca²⁺+2PO₄³⁻+6H₂O
6H⁺ +6OH⁻= 6H₂O
б) Zn - ZnCl₂ - Zn(OH)₂ - ZnO - ZnSO₄ - Zn(NO₃)₂
Zn +2HCI= ZnCl₂+H₂↑
ZnCl₂+2NaOH= Zn(OH)₂↓+2NaCI
Zn²⁺+2Cl⁻+2Na⁺+2OH⁻= Zn(OH)₂↓+2Na⁺+2CI⁻
Zn²⁺+2OH⁻= Zn(OH)₂↓
Zn(OH)₂ +t°C= ZnO+H₂O
ZnO+H₂SO₄= ZnSO₄+H₂O
ZnO+2H⁺+SO₄²⁻= Zn²⁺+SO₄²⁻+H₂O
ZnO+2H⁺= Zn²⁺+H₂O
ZnSO₄+Ba(NO₃)₂ = Zn(NO₃)₂++BaSO₄↓
Zn²⁺+SO₄²⁻+Ba²⁺+2NO₃⁻ = Zn²⁺+2NO₃⁻++BaSO₄↓
SO₄²⁻+Ba²⁺ = BaSO₄↓
в) Na₂O - NaOH - NaHCO₃ - Na₂CO₃ - Na₂SO₄
Na₂O+H₂O=2NaOH
NaOH(изб.)+H₂CO₃=NaHCO₃+H₂O
OH⁻+2H⁺+CO₃²⁻=HCO₃⁻+H₂O
2NaHCO₃+t°60°-200°C= Na₂CO₃+CO₂↑+H₂O
Na₂CO₃+H₂SO₄= Na₂SO₄+CO₂↑+H₂O
2Na⁺+CO₃⁻+2H⁺+SO₄²⁻= 2Na⁺+SO₄²⁻+CO₂↑+H₂O
CO₃⁻+2H⁺= CO₂↑+H₂O