MgCl₂ + Na₂CO₃ = MgCO₃↓ + 2NaCl;
Mg⁺² + 2Cl⁻ + 2Na⁺ + CO₃²⁻ = MgCO₃↓ + 2Na⁺ + 2Cl⁻;
Mg⁺² + CO₃²⁻ = MgCO₃↓.
2HCl + ZnS = ZnCl₂ + H₂S;
2H⁺ + 2Cl⁻ + Zn⁺² + S²⁻ = Zn⁺² + 2Cl⁻ + H₂S;
2H⁺ + S²⁻ = H₂S.
NaOH + HCl = NaCl + H₂O;
Na⁺ + OH⁻ + H⁺ + Cl⁻ = Na⁺ + Cl⁻ + H₂O;
OH⁻ + H⁺ = H₂O.