A) CaO + 2HNO₃ -> Ca(NO₃)₂ +H₂O
CaO + 2H⁺ + 2NO₃⁻ -> Ca²⁺ + 2NO₃⁻ + H₂O
CaO + 2H⁺ -> Ca²⁺ + H₂O
Ca(NO₃)₂ + Na₂CO₃ -> CaCO₃↓ + 2NaNO₃
Ca²⁺ + 2NO₃⁻ + 2Na⁺ + CO₃²⁻ -> CaCO₃↓ + 2Na⁺ + 2NO₃
Ca²⁺ + CO₃²⁻ -> CaCO₃↓
CaCO₃ + 2KCl -> K₂CO₃ + CaCl₂
Ca²⁺ + CO₃²⁻ + 2K⁺ +2Cl⁻ -> 2K⁺ + CO₃²⁻ + Ca²⁺ + 2Cl⁻
б) 4Ca + 10HNO₃ -> 4Ca(NO₃)₂ +N₂O + 5H₂O
Ca⁰ - 2e⁻ -> Ca²⁺ ║4
2N⁺⁵ +4e⁻ * 2 -> N⁺¹ ║1