2NaOH + CaCl₂ = 2NaCl + Ca(OH)₂↓;
2Na⁺ + 2OH⁻ + Ca⁺² + 2Cl⁻ = 2Na⁺ + 2Cl⁻ + Ca(OH)₂↓;
2OH⁻ + Ca⁺² = Ca(OH)₂↓.
K₂CO₃ + Mg(NO₃)₂ = 2KNO₃ + MgCO₃↓;
2K⁺ + CO₃²⁻ + Mg⁺² + 2NO₃⁻ = 2K⁺ + 2NO₃⁻ + MgCO₃↓;
CO₃²⁻ + Mg⁺² = MgCO₃↓.
2NaOH + Zn(NO₃)₂ = 2NaNO₃ + Zn(OH)₂↓;
2Na⁺ + 2OH⁻ + Zn⁺² + 2NO₃⁻ = 2Na⁺ + 2NO₃⁻ + Zn(OH)₂↓;
2OH⁻ + Zn⁺² = Zn(OH)₂↓.
2KOH + CuSO₄ = K₂SO₄ + Cu(OH)₂↓;
2K⁺ + 2OH⁻ + Cu⁺² + SO₄²⁻ = 2K⁺ + SO₄²⁻ + Cu(OH)₂↓;
2OH⁻ + Cu⁺² = Cu(OH)₂↓.