Short answer: No Long answer: It depends on how tight the cotton is packed. Too tight could cause the tube to break or keep gas from escaping. Nevertheless, I'd say in a well ventilated area it should be pretty safe this way. If you want to be 99% safe, you could connect the test tube with a tube leading to a gas washing flask, that contains sodium sulfite.
One way: Reduction with some acid and a primary alcohol, precipitation by neutralising with a base (too much base will dissolve the precipitate again!), filtration, washing and dissolving the precipitate in nitric acid again.
As far as I know it is only stable in an organic solvent like diethyl ether, ethyl acetate or pyridine. However potassium tetraperoxochromate(V) does exist as a dry solid (dark crystals), but it's sensitive to friction and can even explode.
Please I have a school project based on removing hexavalent chromium or converting it to trivalent if I made this experiment will it give me trivalent chromium in the end sure please please answer me
Yes, it's trivalent. In acidic solution it's quite easy to reduce chromium(VI) to green chromium(III) with lots of different reducing agents like f.e. sulfites, thiosulfates, nitrites, iron(II) salts, zinc metal, ethanol or aldehydes. You just have to consider the byproducts, when these reducing agents are oxidized. When the solution is made slightly alkaline afterwards chromium(III) hydroxide could even be filtered off. If it is made too alkaline the hydroxide will dissolve again, forming a complex.
This experiment is also used to test for chromates, so you can try it. Acidify to make sure if there's any Cr(VI) it's present as the dichromate, then add ethyl acetate or diethyl ether on top and at the end a few drops of hydrogen peroxide. If the blue complex doesn't from, no Cr(VI) is present.
Any barium salts available? In slightly acidic solution bright yellow barium chromate precipitates out. I don't know if the sulfate is formed before the chromate, so this could be a issue, but it's worth a try. If no halide is present silver nitrate would also form a reddish brown precipitate.
Dear @Random Experiments International, I'm trying to figure out if low voltage electro-etching of chromium-bearing steels produces Cr(VI) in any form (such as CrO3) but I have no idea how to figure this out. There seems to be a lot of conflicting info out there. My method of electrolysis will be using aqueous iron (II) sulfate as the electrolyte, a hunk of low carbon steel as the cathode and stainless steel (to be etched) as the anode. Your insight here is SUPER appreciated... I'd love to know as much about this as I can above any beyond the Cr(VI) concerns. Best, George
Sorry for answering so late... I'm not a professional if it comes to electro chemistry, but I can understand that people are not sure, whether Cr(VI) is formed or not. Theoretically this shouldn't happen as far as the voltage is low in comparison to the standard electrode potential (I'll call it SEP) of chromium. Nevertheless, in reality these potentials are often more like a guideline, because they depend on a lot of conditions, like the surface of the elctrodes, the electrolyte, the temperature and others. The SEP itself is measured at perfect conditions. One fact that might also be interesting is that chromium(VI) will be reduced by the iron(II) salt as long as it is not used up, but the electrolysis should regenerate it. So it seems, that Cr(VI) even if it might form in traces, will be reduced directly.
Re: Reduction - indeed this was my hope as well - I've read quite a few papers showing the use of FeSO4 for just this purpose and since it makes up the only intentional salt in my electrolyte, I have it in abundance. With that said I'm unsure at what PH the reduction would be achieved. I measured about PH 3 in a 225g/L solution. Thank you for the reply. If I ever figure this out definitively I'll try to reply back here to complete the circle.
I have sulfuric acid and potassium dichromate can i mix these two and use them for plating
Tell me about the testing procedures of total crome
Mn(VII) is also quite dangerous.
Does the cotton wool catch 100% of the aerosol?
Short answer: No
Long answer: It depends on how tight the cotton is packed. Too tight could cause the tube to break or keep gas from escaping. Nevertheless, I'd say in a well ventilated area it should be pretty safe this way. If you want to be 99% safe, you could connect the test tube with a tube leading to a gas washing flask, that contains sodium sulfite.
Hello.I managed to make Sodium Chromate and dichromate but is there any possibility to obtain Chromium Nitrate out of them? Many thanks.
One way: Reduction with some acid and a primary alcohol, precipitation by neutralising with a base (too much base will dissolve the precipitate again!), filtration, washing and dissolving the precipitate in nitric acid again.
I'm looking for a way to create dry peroxo complex.. Is this possible?
As far as I know it is only stable in an organic solvent like diethyl ether, ethyl acetate or pyridine. However potassium tetraperoxochromate(V) does exist as a dry solid (dark crystals), but it's sensitive to friction and can even explode.
Please I have a school project based on removing hexavalent chromium or converting it to trivalent if I made this experiment will it give me trivalent chromium in the end sure please please answer me
Yes, it's trivalent. In acidic solution it's quite easy to reduce chromium(VI) to green chromium(III) with lots of different reducing agents like f.e. sulfites, thiosulfates, nitrites, iron(II) salts, zinc metal, ethanol or aldehydes. You just have to consider the byproducts, when these reducing agents are oxidized. When the solution is made slightly alkaline afterwards chromium(III) hydroxide could even be filtered off. If it is made too alkaline the hydroxide will dissolve again, forming a complex.
I can tell u
+Random Experiments International Aren´t chromates and dichromates carcinogenic only by inalation?
+ChemicalMaster You can also absorb them through your skin or by swallowing them (f.e. getting the dust on your hads and eating food).
+Random Experiments International Do you know any way to see if all the Cr(VI) was completely converted into Cr(III) after adding a reducing agent?
This experiment is also used to test for chromates, so you can try it. Acidify to make sure if there's any Cr(VI) it's present as the dichromate, then add ethyl acetate or diethyl ether on top and at the end a few drops of hydrogen peroxide. If the blue complex doesn't from, no Cr(VI) is present.
+Random Experiments International But I don´t have any ethyl acetate or diethyl ether, so do have any other ideas?
Any barium salts available? In slightly acidic solution bright yellow barium chromate precipitates out. I don't know if the sulfate is formed before the chromate, so this could be a issue, but it's worth a try. If no halide is present silver nitrate would also form a reddish brown precipitate.
Dear @Random Experiments International,
I'm trying to figure out if low voltage electro-etching of chromium-bearing steels produces Cr(VI) in any form (such as CrO3) but I have no idea how to figure this out. There seems to be a lot of conflicting info out there.
My method of electrolysis will be using aqueous iron (II) sulfate as the electrolyte, a hunk of low carbon steel as the cathode and stainless steel (to be etched) as the anode.
Your insight here is SUPER appreciated... I'd love to know as much about this as I can above any beyond the Cr(VI) concerns.
Best,
George
Sorry for answering so late... I'm not a professional if it comes to electro chemistry, but I can understand that people are not sure, whether Cr(VI) is formed or not. Theoretically this shouldn't happen as far as the voltage is low in comparison to the standard electrode potential (I'll call it SEP) of chromium. Nevertheless, in reality these potentials are often more like a guideline, because they depend on a lot of conditions, like the surface of the elctrodes, the electrolyte, the temperature and others. The SEP itself is measured at perfect conditions.
One fact that might also be interesting is that chromium(VI) will be reduced by the iron(II) salt as long as it is not used up, but the electrolysis should regenerate it. So it seems, that Cr(VI) even if it might form in traces, will be reduced directly.
Re: Reduction - indeed this was my hope as well - I've read quite a few papers showing the use of FeSO4 for just this purpose and since it makes up the only intentional salt in my electrolyte, I have it in abundance. With that said I'm unsure at what PH the reduction would be achieved. I measured about PH 3 in a 225g/L solution.
Thank you for the reply. If I ever figure this out definitively I'll try to reply back here to complete the circle.
and the point is
This reaction can be used to test for chromium. And the fact, that an inorganic complex is stable in an organic solvent is also somewhat interesting.
Cancer
@@monarchatto6095 Definetly not
HarukiNoobie I actually don’t remember what I said, I don’t know the context. Maybe it was a joke?
@@monarchatto6095 i dunno,you just said cancer
By uv spectrophotometer