The temporary hardness of water is caused by calcium and magnesium bicarbonate.
On heating temporary hard water, the soluble salts like calcium bicarbonate and magnesium bicarbonate get changed into insoluble carbonate salts and these settle down to the bottom of the container and can be filter away. Example: Ca (HCO3)2 →CaCO3 + CO2+ H2O
Slaked lime converts bicarbonates of calcium and magnesium into carbonates which removetemporary hardness of water.
The temporary hardness of water is thehardness of thewater which is caused due to the presence of soluble bicarbonates of calcium and magnesium which can be removed by boiling.
Slaked lime water of process removing hardness of water called Clark's process.
Soluble salts of calcium and magnesium change into insoluble salts due to the treatment with sodium carbonate (washing soda).
Calcium Chloride + Sodium Carbonate → Calcium Carbonate + Sodium Chloride
CaCl2 + Na2CO3 → CaCO3 + 2NaCl
Magnesium Sulphate + Sodium Carbonate → Magnesium Carbonate + Sodium Sulphate
MgSO4 + Na2CO3 → MgCO3 + Na2SO4