An ion exchange process may be used to remove ions causing hardness of water.

Outline how this works.

1. Ca2+ and Mg2+ are the ions that cause the hardness of water, one example of softening the water is to react the hard water with NaCO3 (Sodium bicarbonate) to soften the water. I don't know how to get the equation to explain this, and how the ion exchange process works to remove the ions.

2. I know how to get rid of the Ca2+ ions, but I don't know if it's enough.

Ca(2+) + 2HCO3(-) --> Caco3 + H2O +CO2
[calcium ion, reacts with bicarbonate to produce calcium carbonate (precipitant), water and carbon dioxide]

:S

2 answers

It is enough.

read about ion exchange.
http://en.wikipedia.org/wiki/Ion_exchange
Ca is trapped in the zeolite, and then periodically, Na is flushed in to remove the Ca ion (goes off in excess NaCl wastewater). when recharged, the zeolite again traps Ca and Mg ions.
I might point out that Na2CO3 is sodium carbonate and not sodium bicarbonate (which is NaHCO3).