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Topic: The effects of salt on the solubility of other substances in water  (Read 1431 times)

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Offline Dorian

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Hi,
I’m trying to cool a water solution to form crystals and wanted to know if I can use table salt to lower the freezing point of the water. The theory behind it, is to enable me to cool the water as much as possible without freezing it. To promote the saturation level of the other solute and maximise the yield (i.e. the percentage of the solute that crystalised).

What I would like to know, is adding salt to the solution going to affect the solubility of the other solute?

If so, what is the mechanism by which the solubility of the solute is altered?

E.g. Is it because the salt uses up some of the capacity of the water to dissolve anything else (e.g. adding some salt to water would reduce how much more salt that water could dissolve, except in this case it’s two different solutes, though same idea).
Or
Does the salt change the chemical properties of the water, either increasing/decreasing its ability to dissolve other substances.

Lastly, whatever the case may be, how do you determine the effect (if any) salt has on the solubility of other substances in water?

Offline Corribus

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Re: The effects of salt on the solubility of other substances in water
« Reply #1 on: December 10, 2018, 08:41:31 AM »
Typically the solubility of electrolytes increases with increasing ionic strength.

https://pubs.acs.org/doi/abs/10.1021/ed081p1644?journalCode=jceda8
What men are poets who can speak of Jupiter if he were like a man, but if he is an immense spinning sphere of methane and ammonia must be silent?  - Richard P. Feynman

Offline jeffmoonchop

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Re: The effects of salt on the solubility of other substances in water
« Reply #2 on: December 10, 2018, 01:47:27 PM »
use a different solvent, or use more solute, or less solvent.

Offline Babcock_Hall

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Re: The effects of salt on the solubility of other substances in water
« Reply #3 on: December 10, 2018, 02:46:57 PM »
I only have time for a brief, offhand reply right now.  However, a high concentration of salt can decrease the solubility of an organic compound.  If you Google salting out benzene, that might get you started.

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