1) Na → Na₂O₂ → Na₂O → NaOH → Na₂SO₄
1. 2Na + O₂ → Na2O2
2. Na₂O₂ + 2Na → 2Na₂O
3. Na₂O + H₂O → 2NaOH
4. 2NaOH + H₂SO₄ → Na₂SO₄ + H₂O
2) Ca → CaO → Ca(OH)₂ → Ca(NO₃)₂ → CaCO₃
1. 2Ca + O₂ → 2CaO
2. CaO + H₂O → Ca(OH)₂
3. Ca(OH)₂ + 2HNO₃ → Ca(NO₃)₂ + H₂O
4. Ca(NO₃)₂ + H₂CO₃ → 2HNO₃ + CaCO₃