Na₂CO₃ + СaCl₂ = СaCO₃↓ + 2NaCl
2Na⁺ + CO₃²⁻ + Сa²⁺ + 2Cl⁻ = СaCO₃↓ + 2Na⁺ + 2Cl⁻
Сa²⁺ + CO₃²⁻ = СaCO₃
K₂CO₃ + 2HNO₃ = 2KNO₃ + CO₂↑ + H₂O
2K⁺ + CO₃²⁻ + 2H⁺ + 2NO₃⁻ = 2K⁺ + 2NO₃⁻ + CO₂↑ + H₂O
2H⁺ + CO₃²⁻ = CO₂↑ + H₂O
2Na + 2H₂O = 2NaOH + H₂
2Na + 2H₂O = 2Na⁺ + 2OH⁻ + H₂