Page 3 - LN
P. 3

  Permanent hardness can be removed by treating the water with washing
                       soda.
                     By boiling hard water with sodium carbonate, the chlorides and sulphates of
                       calcium and magnesium get converted, to sodium chloride and sodium
                       sulphate respectively.
                     The insoluble precipitates of calcium and magnesium carbonates are
                       removed by filtration.
                     Chlorides and sulphates of sodium remain in the solution.
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