Question

The hardness of water is due to the presence of:

• A. calcium and magnesium salts
• B. sodium and magnesium salts
• C. calcium and sodium salts
• D. ammonium and sodium salts

Answer 1

The correct option is A calcium and magnesium salts

Hardness of water is due to the presence of chlorides and sulphates of calcium and magnesium. It can be removed by adding sodium carbonate $\left({\text{Na}}_2{\text{CO}}_3\right)$ or boiling.