Hardness of water is mainly due to the presence of
-
A.
calcium hydroxide or magnesium hydroxide -
B.
calcium trioxocarbonate (IV) or calcium tetraoxosulphate (VI) -
C.
sodium hydroxide or magnesium hydroxide -
D.
calcium chloride or sodium chloride salts
Correct Answer: Option B
Explanation
Salts of Calcium and Magnesium are responsible for hardness of water. Bicarbonates, Carbonates, Chlorides and Sulfates of Calcium and Magnesium causes temporary and permanent hardness.