Page 53 - Statistics presented by Dr. Sara Ismail Aborass

9/8/2023

(D) OTHER METALS

-Zinc, Copper, Manganese and other metals may
be present in water.
-The maximum allowed limit of certain metals
must not exceed certain values.
-The concentration of any of these metals can be
determined by atomic absorption spectrometry.

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[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.

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