# Can dissolved salts (or any soluble chemicals, for that matter) 'bump' each other out of solubility?

Will a more soluble substance dissociate, causing a less soluble substance to precipitate out?

in equation:

AB(s)+ C(aq)+ D(aq)--> A(aq)+ B(aq)+ CD(s)

Does that equation go through, under the assumptions that AB, as a whole, is more soluble than CD, and saturation point is achieved with both substances?

Thanks in advance! This question has been bothering me for a while...

## 1 Answer

Yes, this effect is termed salting out for non-ionic compounds and the common ion effect for ionic ones.

Note that in specific cases, the converse may hold true. For example, "the solubility of silver chloride in water is reduced if a solution of sodium chloride is added to a suspension of silver chloride in water (op cit)." However, adding more chloride re-dissolves the precipitate due to the formation of complex ions:

$\ce{AgCl(s) + Cl- (aq) -> AgCl2- (aq)}$

• I don't think the OP was asking about the common ion effect. More like $$\ce{KNO3_{(s)} + Ag^+_{(aq)} + Cl^{-}_{(aq)} -> K^+{(aq)} + NO3^{-}_{(aq)} + AgCl_{(s)}}$$ which I think would have the opposite effect. I'd expect $\ce{AgCl}$ to be more soluble in a $\ce{KNO3}$ solution. – MaxW Dec 2 '15 at 1:18
• Yeah that's what I was thinking. So if I was to put sugar into saturation point salt water, the salt would precipitate out? – Clint Dec 3 '15 at 2:21