Chlorinated Coppers:

Ferrous Sulphate (Coppers) with chlorine is called chlorinated coppers, which is extremely effective in drinking water treatment over a wide range of pH. The relevant reaction follows:

6 FeSO₄ + 3Cl₂ → Fe₂ (SO₄)₃ + 2FeCl₃ (ppt).

2FeSO₄ + 3Ca(HCO₃)₂ + Cl₂  → Fe (OH)₃ + 2CaSO₄ + CaCl₄ + 6CO₂

(ppt)   (ppt)

With hydrated lime, coppers reacts as follows:

FeSO₄.7H₂O + Ca (OH₃)₂  → Fe(OH)₂ + CaSO₄

Fe (OH)₂ + O + H₂O → Fe (OH)₃