:Sodium carbonate and sodium bicarbonate vs hard water


There are claims that sodium bicarbonate
does not soften hard water the way sodium carbonate does. Is this true? Why does the hydrogen make such a big difference?


In: 1

Sodium carbonate releases 2 sodium ions into solution while sodium bicarbonate only releases 1.

When dissolved, sodium carbonate releases two sodium with a charge of +1 each and carbonic acid with a charge of -2.

Hard water is formed due to the presence of calcium and/or magnesium ions in the water. These have a charge of +2, and will bind to the carbonic acid. When they do, the calcium/magnesium carbonate that forms cannot dissolve in water, and will precipitate out.