Question

Hardness of water is due to

• A. Chloride of calcium
• B. Bicarbonate of magnesium
• C. Sulphate of aluminium
• D. Both (A) & (B)

Answer 1

The correct option is D

Both (A) & (B)

The explanation for the correct option:

(D) Both (A) & (B)

• The hardness of water is due to Chloride of calcium and Bicarbonate of magnesium.
• Hard water contains soluble salts of calcium and magnesium.
• It does not give lather with soap. this is because of the precipitation of the insoluble soap
• The explanation for the incorrect option:

(A) Chloride of calcium: it is a salt of calcium so, It can cause hardness but bicarbonate of magnesium can also cause hardness

(B) Bicarbonate of magnesium: it is a salt of magnesium so, It can cause hardness but Chloride of calcium can also cause hardness

(C) Sulphate of aluminum: it is not salt of calcium and magnesium so it cannot cause hardness.

Thus option (D) is the correct answer, Hardness of water is due to Chloride of calcium and Bicarbonate of magnesium.