Science4561
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Prussian blue test
I have potassium cyanide that I need to run testing on, because I’m unsure whether it’s really just that.
Now, I understand there are several different methods to use for this matter. One of them is using this method to create Prussian blue:
https://gfycat.com/constantbreakablehypsilophodon
Is it a must to do this test under a fume hood in lab gear?
I understand that acidifying and then pouring it in that solution will make gas?
How would I test it, in your view, in the safest possible way?
I really need to know it’s cyanide.
Thank you.
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MidLifeChemist
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Here are some methods:
Add ammonia to Nickel Sulfate until you get a deep blue color. This is a hexaamine complex.
Then add your cyanide. There will be a precipitate which will redissolve, forming a yellow (CN-)4 complex with Nickel.
Alternatively, you can try to dissolve AgBr or AgI in your a solution of your cyanide salt. If it is cyanide, it will dissolve Silver halides forming
the Ag(CN)2 - complex.
There are also various complexes with Copper (II). Your cyanide solution should dissolve black CuS.
Good luck! And be careful. But this should be safer than a method involving gas.
[Edited on 12/5/2020 by MidLifeChemist]
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Science4561
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Quote: Originally posted by MidLifeChemist  | Here are some methods:
Add ammonia to Nickel Sulfate until you get a deep blue color. This is a hexaamine complex.
Then add your cyanide. There will be a precipitate which will redissolve, forming a yellow (CN-)4 complex with Nickel.
Alternatively, you can try to dissolve AgBr or AgI in your a solution of your cyanide salt. If it is cyanide, it will dissolve Silver halides forming
the Ag(CN)2 - complex.
There are also various complexes with Copper (II). Your cyanide solution should dissolve black CuS.
Good luck! And be careful. But this should be safer than a method involving gas.
[Edited on 12/5/2020 by MidLifeChemist] |
Thanks a lot. On the hexamine complex method, what would be required on the percentage of the NH3?
Also, how much cyanide should I add ?
Did I understand you correct if the solution should turn yellow in the end? Or its just a momentary change into yellow?
[Edited on 6-12-2020 by Science4561]
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unionised
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Cu(II) ions will oxidise CN- to (CN)2
That's not what we want to do.
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