Permanent hardness of water is due to the presence of __________?

A. Sodium bicarbonate
B. Calcium sulfate
C. Calcium bicarbonate
D. None of these

Explanation:

Permanent hardness in water is due to the presence of chlorides, nitrates, and sulfates of calcium and magnesium. It is not precipitated by boiling. These minerals in water can cause some everyday problems. Hard water may also shorten the life of plumbing and water heaters. The limescale can build up on the inside of the pipe restricting the flow of water or causing a blockage.