Ask A Scientist© Chemistry Archive

name         John R.
status       educator
age          50s

Question -   My apologies for confusing wording of previous question -
it was typed by my well meaning Indonesian lab attendant

The question again is:

How is the solubility of strontium carbonate influenced by the addition of
a solution of (say) .1M barium nitrate - given that barium carbonate is
insoluble?
I have fiddled with some maths and my result is counter-intuitive.
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Near as I can figure this problem, if you add barium nitrate to strontium
cagbonate, the barium and carbonate will precipitate out together as barium
carbonate, leaving strontium and nitrate behind in solution.  So more
strontium will be able to go into solution, as strontium nitrate is a lot
more soluble in water then strontium carbonate.  Strictly speaking, the
solubility of the strontium carbonate is not changing - The solubility
product [Sr++][CO3--] never exceeds its maximum value.  I think of the
process of substituting strontium nitrate for strontium carbonate.

This assumes that barium carbonate is less soluble in water than strontium
carbonate.  I think this is the case, but I haven't looked it up.  I am
certain that the nitrates are more soluble than the carbonates.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois
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