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Author: Subject: Chemical Salts solubility question
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[*] posted on 1-9-2015 at 18:47
Chemical Salts solubility question

I made a bit of gallium nitrate by adding KNO3 to H2SO4. The nitric acid dissolved the Gallium, but as expected left some Potassium sulfate with it. I was just messing around since I don't have the means to distill nitric acid (no fumehood). I read, thanks to all of you, that Gallium nitrate is very soluble in water. Potassium sulfate is very insoluble in water, correct? I think if I just add some water I can filter off most of the Potassium Sulfate.

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[*] posted on 1-9-2015 at 21:06

Why would you add extra water? Unless your Gallium nitrate has not completely dissolved, adding water would only decrease the amount of Potassium Sulfate remaining in solution.
You will also have some KNO3 and H2SO4 remaining in solution, and so to separate out the gallium from this mixture will be very difficult without changing the gallium into another form e.g. Gallium carbonate.
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[*] posted on 2-9-2015 at 03:06

mhm......I see so many people here using cheap mineral acids mixed with salts somet even add peroxides
to it in the hope it will react better. I think there is a certain level that you need to start from. You either
have access to Nitric Acid which is hard, I know that or you will have to distill some. But as you saw the
chemistry of Gallium is not that easy. You are so lucky that the Galliumsulfate is soluble and didn't just fall
out as an unreactive salt. The question is how to get is seperated now. Carbonate could be a simple method
the problem is that basic Gallium Sulfate is insoluble. So I dunno about the reactions of the Sulfate I'd have
to check that but you have to be careful that you don't accidentally turn your now usefull Nitrate into an
unreactive insoluble Salt.... I will check that in the Gmelin later if it says anything about sulfate or carbonates
maybe there is an easy way to seperate it.

But that is one of the reasons why I will probably order some Thalliumsalts in the future and use them
in stead of Silver Salts. For my Cyanide Compounds there are some Cyanometallates that can only be
precipitated by either Silver or Thallium but the question is how do you prepare that compound without
having any Anion in there that would react with Silver. Nearly all Silver Salts are insoluble which makes it
hard to find something. Thallium is easier here and although it's really toxic it might be more usefull than silver
sometimes. And that is basically what I suggest you have to keep an eye on while working with Gallium.
That stuff is expensive and if you want to repeat certain text you should really stick to the chemicals they used.

In organic chemistry that is a lot easier since you can destill stuff or extract it, I always though cleaning stuff
in the OC was way easier that in inorganic chemistry. And so is the planning of your experiment. You have to
take every ion in your solution into consideration which is sometimes really dificult. One really good way if your
are handling heavy metals is what Oscillator said, using Carbonates to seperate it, clean it and then nitric acid again
to get a pure solution.

[Edited on 2-9-2015 by fluorescence]
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[*] posted on 3-9-2015 at 08:14

K2SO4 is 7.4g at 0*C 100mL H2O
i think lower than 5.0g classifies something as "insoluble" or at least not very soluble
very useful bookmark

you may as others suggested need to convert the gallium into an insoluble salt, maybe exploit decantation.. doesnt take more than an hour for magnesium hydroxide to settle, gallium carbonate should settle much faster

~25 drops = 1mL @dH2O viscocity - STP
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[*] posted on 25-9-2015 at 23:48

I have found the Wikipedia solubility table so useful that I downloaded it into open office calc.
I also made a calc spreadsheet with one tab per alphabet of name which is attached in .ods and one in .xls (95)

Attachment: AlphabeticalSolubilityOfSalts.ods (52kB)
This file has been downloaded 254 times

Attachment: AlphabeticalSolubilityOfSalts.xls (115kB)
This file has been downloaded 265 times
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