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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: bubblegumpi on December 18, 2019, 01:14:47 PM

Title: Can Acids still disolve things if the solution is saturated?
Post by: bubblegumpi on December 18, 2019, 01:14:47 PM
If you were dissolving zinc in HCl and water and the solution is nearing saturation but the acid is still "not used up" will it go super saturated as you keep adding zinc strips? What stops the reaction first, acid depletion or solution saturation? I'm sure there are better acids and metals or reactants to use in this example but zinc came to mind. If the solution is saturated with another metal first, say copper strips to saturation, will it still be possible to dissolve additional zinc? What would happen totwo totally different solutes like sugar into saturated NaCl water solution?
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: chenbeier on December 18, 2019, 01:48:45 PM
You will get precipitation, but the acid will still do the work.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: Enthalpy on December 19, 2019, 02:37:20 PM
It's not a matter of solubility.

If you dissolve table salt in water, you expect to regain the salt by evaporating the water.
After attacking zinc with hydrochloric acid, you won't regain zinc by evaporation.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: bubblegumpi on December 19, 2019, 02:38:21 PM
You will get precipitation, but the acid will still do the work.

What happens if already saturated with another metal or another substance that's not ionic like sugar?
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: AWK on December 19, 2019, 05:05:04 PM
If the solutes do not interact with each other, in the absence of a common ion, they can be expected to show solubility independent of each other. Solutions of saturated sucrose with ZnCl2 are used in density gradient centrifugation.  The available gradient ranges from 1.2 to 2.0 g/cm3.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: shchavel on December 22, 2019, 01:35:07 AM
Read about Diverse Ion Effecton Solubility, for example in Cristian Analytical Chemistry (10.6)
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: bubblegumpi on December 22, 2019, 06:15:44 PM
Read about Diverse Ion Effecton Solubility, for example in Cristian Analytical Chemistry (10.6)

Will try but many of these papers are behind paywalls.

I'm curious to saturate a polar solution with as many solutes and other things like sugar as possible. There has to be a point where it just go too much in it and things don't go into solution. Wish I had a lab to try that. Kitchen sink doesn't have enough reagents.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: Borek on December 22, 2019, 06:55:27 PM
There has to be a point where it just go too much in it and things don't go into solution.

That's more or less how it is. Broadly speaking solution requires the dissolved molecules or ions to have solvation shells. Once there are too many things dissolved there is not enough water molecules for that and solutes start to compete for them.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: chenbeier on December 23, 2019, 01:40:39 AM
It's not a matter of solubility.

If you dissolve table salt in water, you expect to regain the salt by evaporating the water.
After attacking zinc with hydrochloric acid, you won't regain zinc by evaporation.

Thats is a different Topic. Here nobody want to get salt or zinc obtained by evaporation. Also you mixed a physical processes dissolving salt in water with a chemical process. Hydrochloric reacts with zinc.

Here Zinc is dissolved in hydrochloric. The question was what happened the solution get saturated. Do zinc still dissolve. In my opinion the zinc chloride precipitate but zinc will stll dissolved from the acid.
Title: Re: Can Acids still disolve things if the solution is saturated?
Post by: bubblegumpi on December 24, 2019, 09:08:24 AM
It's not a matter of solubility.

If you dissolve table salt in water, you expect to regain the salt by evaporating the water.
After attacking zinc with hydrochloric acid, you won't regain zinc by evaporation.

Thats is a different Topic. Here nobody want to get salt or zinc obtained by evaporation. Also you mixed a physical processes dissolving salt in water with a chemical process. Hydrochloric reacts with zinc.

Here Zinc is dissolved in hydrochloric. The question was what happened the solution get saturated. Do zinc still dissolve. In my opinion the zinc chloride precipitate but zinc will stll dissolved from the acid.

So you could use this technique to dissolve out two water soluble things: Supersaturate Solute A then add acid the solute B crashing solute A out of the solvent? This seems like it would have a lot of uses when you have but polar solvents and no way to selectively crash just one out. Seems too good to be true though what would the yield look like?