Temporary and permanent magnets

How are temporary and permanent hardness removed ?

What causes the temporary and permanent hardness of water ?

Both temporary and permanent hardness is removed on boiling with

Name a process which can remove both temporary and permanent hardness of the water.

Give reasons for the following: Washing soda can be used to remove both temporary and permanent hardness in water.

Permanent magnets show

Distinguish clearly between temporary and permanent hardness.

The desirable properties for making permanent magnets are

25mL samples of distiled water, tap water and boiled water required, respectively, 1mL, 13mL and 5mL of soap solution to form a permanent lather. The ratio of temporary to permanent hardness in the tap water is

Assertion: Substances which at room temperature retain their ferromagnetic property for a long period of time are called permanent magnets. Reason: permanent magnet can be made by placing a ferramagnetic rod in a solenoid and passing current through it.