Hardness of water may be temporary or permanent. Permanent hardness is due to the presence of
A. Chlorides of Ca and Mg in water
B. Sulphates of Ca and Mg in water
C. Hydrogen carbonates of Ca and Mg in water
D. Carbonates of alkali metals in water
Permanent hardness in water is caused due to the presence of soluble salts of magnesium and calcium in the form of chlorides or sulphates in water.
So the chlorides as well as sulphates are responsible for causing permanent hardness in water.
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