How do we find gram solubilities of metal hydroxides?

1 Answer
Apr 30, 2017

Answer:

You need to quote #K_"sp"# values for the hydroxides of metal ions........

Explanation:

The #K_"sp"# values are of course available in the literature, and SHOULD have been included in the question.

Once we have #K_"sp"# values, then we can address the various solubility. For calcium chloride we approach this in this manner........

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

Now #K_"sp"=[Ca^(2+)][HO^-]^2#.

And if we call the solubility of calcium chloride, #S#, then #S=[Ca^(2+)]#, and #[Cl^-]=2S# (provided there is no extraneous source of calcium and chloride ions......)

So #K_"sp"=Sxx(2S)^2=4S^3#.

And #S=""^3sqrt((K_"sp")/4)#.

And so without #K_"sp"# we are at an impasse. Such calculations require prior measurement or reference to the literature data.