б)
Ca + 2H₂O = Ca(OH)₂↓ + H₂↑;
Ca(OH)₂ + CO₂ = CaCO₃↓ + H₂O;
CaCO₃ = CaO + CO₂↑;
CaO + 2HCl = CaCl₂ + H₂O;
CaCl₂ + Na₂CO₃ = CaCO₃↓ + 2NaCl.
в)
4Al + 3O₂ = 2Al₂O₃;
Al₂O₃ + 6HCl = 2AlCl₃ + 3H₂O;
AlCl₃ + 3NaOH = Al(OH)₃↓ + 3NaCl;
2Al(OH)₃ + 6Na = 2Na₃AlO₃ + 3H₂↑.