Question

Name four salt which cause permanent hardness of water

Answer 1

Salts of Calcium and Magnesium are responsible for hardness of water. Bicarbonates, Carbonates, Chlorides and Sulphates of Calcium and Magnesium causes  permanent hardness.

Answer 2

Answer:

Salts that cause permanent hardness of water:

Magnesium Sulphate (MgSO₂)

Magnesium chloride (MgCl₂)

Calcium carbonate ( CaCO₃)

Calcium Sulphate ( CaSO₄)

These are the salts that cause permanent hardness of water.

Explanation:

Permanent hardness

Permanent hardness of water is caused by salts that do not dissociate even upon heating.

These salts include the calcium, carbonate and chloride of both magnesium and calcium.

Examples include; Magnesium Sulphate (MgSO₂), Magnesium chloride (MgCl₂), Calcium carbonate ( CaCO₃) , Calcium Sulphate ( CaSO₄)

Temporary hardness

Temporary hardness of water on the other hand can easily be removed by boiling the water.

Temporary hardness is caused by Magnesium hydrogencarbonate Mg(HCO₃)₂and Calcium hydrogencarbonate Ca(HCO₃)₂.

These two salts easily dissociate upon heating to remove the hardness.