Question

Which of the following salt is used for removing the permanent hardness of water?

(a)Washing soda

(c)Bleaching powder

(b)baking soda

(d)NaOH​

Answer 1

Correct answer is Option (a) Washing soda

Permanent hardness of water is the hardness caused by calcium and magnesium salt of sulphate, chloride and nitrate.

Explanation:

• Permanent hardness is the hardness that cannot be removed by mere boiling

• It can be removed by adding chemicals

• Thus chemical which can remove the calcium and magnesium salts of sulphates and nitrates is Washing soda

• Washing soda is Na₂CO₃

• Sodium carbonate is a disodium salt that can remove this hardness causing salt.

• Sodium ions help to remove the calcium and magnesium ions present in the hard water.

Answer is Option (a) Washing Soda is used for removing the permanent hardness of water.

Answer 2

Answer:

correct answer is option (a)