Which anions produce permanent hardness in water?

What causes permanent hardness of water ?

Permanent hardness of water is due to

By adding which of the following process, permanent hardness of water can be removed.

By adding which of the following process, permanent hardness of water can be removed.

Name the salts that lead to the formation of permanent hardness in water can you remove permanent hardness by boiling?

Name the anions responsible for permanent hardness of water