Question

Saturation with which of the following substances will produce hard water?

• A. Saturation of water with $CaC{O}_3$
• B. Saturation of water with $MgC{O}_3$
• C. Saturation of water with $CaS{O}_4$
• D. Saturation of water with $N{a}_{2}S{O}_4$

Answer 1

The correct option is C

Saturation of water with $CaS{O}_4$

The water in which the soaps do not lather easily is called hard water. It contains dissolved salts of chlorides and sulphates of calcium and magnesium.

Therefore, the saturation of water with calcium sulphate, magnesium sulphate, calcium chloride and magnesium chloride will make the water hard.