Question

Which salt does not cause hardness in water?

• A. Calcium
• B. Sodium
• C. Magnesium
• D. Both 1 & 3

Answer 1

The correct option is B

Sodium

Explanation:

Hard water: The water which does not produce lather with the soap and forms a precipitate or scum is known as hard water.

Reason behind hardness of water:

• The reason behind the hardness of water is the presence of bicarbonates, chlorides, and sulphate of magnesium and calcium which do not allow the water to form a lather with soap.
• So, these salts of magnesium and calcium are responsible for the hardness of the water.

Hence, Sodium salts are not responsible for the hardness of the water.

Hence, the correct option is (B).