Question

the chemical substance used for Removal of permanent hardness of water is a. bleaching powder b. washing soda c. baking soda d. plaster of paris​

Answer 1

The chemical substance used for removal of permanent hardness of water is Washing soda that is sodium carbonate .

Hope it will u !!!

Answer 2

Answer:

Option b. Washing soda

Explanation:

• Plaster of Paris $(CaSO_{4}.\frac{1}{2}H_{2} O)$ is a chemical compound prepared from heating gypsum. It is often used by doctors in plasters for supporting fractured bones.

Thus option d is incorrect.

• Sodium Bicarbonate  $(NaHCO_{3})$ or baking soda. It is most commonly used in cooking recipes.

Thus option c. is incorrect.

• Bleaching powder ($CaOCl_{2}$)-Calcium hypochlorite is most often used as an oxidizer in many industries and as a disinfectant to make potable water.

Thus option a. is incorrect.

• The concentration of mineral ions such as calcium and magnesium ions in a sample of water is called the hardness of the water.
• This hardness of water is of two types i.e. permanent and temporary.
• Temporary hardness is easy to remove just by boiling it.
• The permanent hardness of water is caused due to the presence of chlorides and sulfates of calcium and magnesium contents can be removed by using washing soda ($Na_{2}CO_{3}$)
• Sodium Carbonate or washing soda is used to remove the permanent hardness .

Hence option b. washing soda is correct.