Question:
The hardness of water may be temporary or permanent. Permanent hardness is
due to the presence of
(i) Chlorides of Ca and Mg in water
(ii) Sulphates of Ca and Mg in water
(iii) Hydrogen carbonates of Ca and Mg in water
(iv) Carbonates of alkali metals in water
Solution:
Option (i) and (ii) are the answers.