Question

What are the causes of the permanent hardness of water?

Answer 1

• When the soluble salts of magnesium and calcium are present in the form of chlorides and sulfides in water, we call it permanent hardness because this hardness cannot be removed by boiling.
• We can remove this hardness by treating the water with washing soda. Insoluble carbonates are formed when washing soda reacts with the sulfide and chloride salts of magnesium and calcium and thus, hard water is converted to soft water.