Chemgineer
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Sulphuric acid from nitric acid
I normally produce sulphuric acid by bubbling sulphur dioxide through a 50% solution of nitric acid. The solution goes from yellow to green, releases
copious amounts of nitrogen dioxide and eventually goes clear when it is mostly sulphuric acid.
I use a sulphur dioxide generator consisting of sodium metabisulphite and hydrochloric acid which is bubbled through the nitric acid which is sat in a
cooling bath.
Towards the end of this reaction I start to get a white foam and build up on the walls of the flask. I notice when cleaning the flask, this white
deposit when mixed with water immediately dissolves and produces red nitrogen dioxide gas.
Does anyone have any idea what this foam, white deposit might be?
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Chemgineer
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I should say, as for the sulphuric acid, I next boil it until it produces an acrid smell and white fumes then allow it to cool, it ends up around 80%
I believe.
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Sir_Gawain
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Assuming your reagents are pure, the only thing I can think of is nitrosylsulfuric acid.
“Alchemy is trying to turn things yellow; chemistry is trying to avoid things turning yellow.” -Tom deP.
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bnull
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Nitrosylsulfuric acid (https://www.sciencemadness.org/smwiki/index.php/Nitrosylsulf... and https://onlinelibrary.wiley.com/doi/10.1002/9780470132326.ch...).
Edit: victim of ninja attack... again.
[Edited on 23-5-2024 by bnull]
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Chemgineer
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Thanks, it seems this breaks down into nitrogen dioxide at 70 deg C which is fine so my sulphuric acid will be purified by my final heating step.
Now my only problem is hcl has been restricted here to 11% max, I might need to explore some other sulphur dioxide generator methods.
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RU_KLO
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Quote: Originally posted by Chemgineer  | Thanks, it seems this breaks down into nitrogen dioxide at 70 deg C which is fine so my sulphuric acid will be purified by my final heating step.
Now my only problem is hcl has been restricted here to 11% max, I might need to explore some other sulphur dioxide generator methods.
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Check Nurd Rage Youtube channel for other methods of Sulfuric acid preparation.
Go SAFE, because stupidity and bad Luck exist.
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