3) NaCI+AgNO₃=NaNO₃ +AgCI
4) S→SO₂→H₂SO₃→Na₂SO₃→ SO₂
S + O₂ = SO₂
SO₂ + H₂O = H₂SO₃
H₂SO₃ + 2NaOH = Na₂SO₃ + 2H₂O
5) AI→AI₂(SO₄)₃→AI(OH)₃ →AI₂O₃→AI(NO₃)₃
2AI + 3H₂SO₄ = AI₂(SO₄)₃ + 3H₂↑
AI₂(SO₄)₃ + 6NaOH = 2AI(OH)₃ + 3Na₂SO₃
2AI(OH)₃ + = AI₂O₃+ 3H₂O
AI₂O₃ + 6HNO₃= 2AI(NO₃)₃+ 3H₂O
6) Fe→FeCI₃→Fe(OH)₃→Fe₂(SO₄)₃
2Fe + 3CI₂ = 2FeCI₃
FeCI₃ + 3NaOH = Fe(OH)₃↓ + 3NaCI
2Fe(OH)₃ + 3H₂SO₄ = Fe₂(SO₄)₃ + 6H₂O