How to write net ionic equation for calcium carbonate with potassium hydroxide?

1 Answer
anor277
Jun 16, 2018

Well, we might be able to....but both calcium carbonate and calcium hydroxide are pretty insoluble in aqueous solution....

Explanation:

And so for the precipitation of #"calcium hydroxide"# we would write...

#Ca^(2+) + 2HO^(-) rarr Ca(OH)_2(s)darr#

But we don't know a priori which salt is the more insoluble...i.e. calcium hydroxide, or calcium carbonate. I think it is calcium carbonate...but as chemists, as physical scientists, we must have recourse to the data, which were NOT provided in the question.

This site reports that #K_"sp"# for the carbonate salt is #3.3xx10^-9# which gives a solubility of approx. #"6 ppm"# (NB #"1 ppm"-=1*mg*L^-1#). For calcium hydroxide, this site reports #K_"sp"=5.5xx10^-6#..a molar solubility of approx. #2*g*L^-1#. So the hydroxide is MORE soluble than the carbonate... The question was not well-proposed.

Related questions
Impact of this question
2400 views around the world
You can reuse this answer
Creative Commons License