Verified answer

А)
2Ba + O₂ = 2BaO

BaO + H₂O = Ba(OH)₂

Ba(OH)₂ + HNO₃ = Ba(NO₃)₂ + H₂O
Ba(NO₃)₂ + H₂SO₄ = BaSO₄ + 2HNO₃

Б)
4Al + 3O₂ = 2Al₂O₃
Al₂O₃ + 6HCl = 2AlCl₃ + 3H₂O
AlCl₃ + 3NaOH (нед.) = Al(OH)₃ + 3NaCl
2Al(OH)₃ = Al₂O₃ + 3H₂O
Al₂O₃ + 3SO₃ = Al₂(SO₄)₃

В)
Fe + Fe₂O₃ = 3FeO
FeO + 2HCl = FeCl₂ + H₂O
FeCl₂ + 2NaOH = 2NaCl + Fe(OH)₂
Fe(OH)₂ = FeO + H₂O

FeO + SO₃ = FeSO₄

Г)
C + O₂ (изб.) = CO₂
CO₂ + H₂O = H₂CO₃

H₂CO₃ + CaO = CaCO₃ + H₂O

CaCO₃ = CaO + CO₂

CaO + HCl = CaCl₂ + H₂O