When zeolite is treated with hard water,the sodium ions are exchanged with:

Hard water contains ions of

Identify the correct statements from the following.
$A$. In photosynthesis reaction,water is oxidized to oxygen.
$B$. An example for interstitial hydride is $MgH_2$.
$C$. Sodium hexametaphosphate is used in the removal of permanent hardness of water.

Temporary hardness of water can be removed by

Which process is used for the removal of hardness of water?

Write two reactions to explain the amphoteric nature of water.