Na₂CO₃ + 2HCl = 2NaCl + CO₂↑ + H₂O;
2Na⁺ + CO₃²⁻ + 2H⁺ + 2Cl⁻ = 2Na⁺ + 2Cl⁻ + CO₂↑ + H₂O;
CO₃²⁻ + 2H⁺ = CO₂↑ + H₂O.
NaOH + HCl = NaCl + H₂O;
Na⁺ + OH⁻ + H⁺ + Cl⁻ = Na⁺ + Cl⁻ + H₂O;
OH⁻ + H⁺ = H₂O.
Fe(OH)₂↓ + 2HNO₃ = Fe(NO₃)₂ + H₂O;
Fe(OH)₂↓ + 2H⁺ + 2NO₃⁻ = Fe²⁺ + 2NO₃⁻ + H₂O;
Fe(OH)₂↓ + 2H⁺ = Fe²⁺ + H₂O.
Mg + H₂SO₄ = MgSO₄ + H₂↑;
Mg⁰ + 2H⁺ + SO₄²⁻ = Mg²⁺ + SO₄²⁻ + H₂↑;
Mg⁰ + 2H⁺ = Mg²⁺ + H₂↑.