Page 102 - Pharmaceutical Analytical Chemistry III

[5]HARDNESS OF WATER

Waters are usually classed as “hard” or “soft” according
to their action in soap. The less the amount of soap
required to produce lather the softer the water.

There are two types of hardness of H2O :
(a) Temporary Hardness : Is due to the bicarbonate of

calcium and magnesium. Temporary hardness is
destroyed by boiling.

(b) Permanent Hardness : Is due to the presence of
sulphates, chlorides and nitrates of calcium and
magnesium.