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Author: Subject: H2O2 vs Acids, injuries and pain
Syn the Sizer
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[*] posted on 12-6-2020 at 11:55


Good point, I have never dealt with 99% HNO3.
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Chemorg42
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[*] posted on 12-6-2020 at 13:56


Would fuming nitric (small amount of water) be less or more hazardous than pure nitric (no water at all?)



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[*] posted on 12-6-2020 at 17:44


I never heard about 100% HNO3. White fuming nitric acid can exist in concentrations up to 99%, but it never be 100%. But it's less reactive than red fuming nitric acid which contain lots of NO2.



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Syn the Sizer
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[*] posted on 12-6-2020 at 18:05


Also doesn't nitric acid and most other acids react more when a small amount of water is present? So 99% white fuming acid is less reactive than 99% white fuming nitric acid that has been diluted slightly?
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Chemorg42
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[*] posted on 12-6-2020 at 19:19


Both of you, yes, I was mistaken. I new I had read something about water and fuming nitric acid, but I couldn't remember what.
So my new question is, which is more corrosive, red or white fuming nitric acid?




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Syn the Sizer
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[*] posted on 12-6-2020 at 20:35


Quote: Originally posted by Chemorg42  
Both of you, yes, I was mistaken. I new I had read something about water and fuming nitric acid, but I couldn't remember what.
So my new question is, which is more corrosive, red or white fuming nitric acid?


I could not say for certain. But I believe red would be more corrosive due to the dissolved NO2(g).

[Edited on 13-6-2020 by Syn the Sizer]
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[*] posted on 15-6-2020 at 07:04


Quote: Originally posted by Syn the Sizer  
Also doesn't nitric acid and most other acids react more when a small amount of water is present? So 99% white fuming acid is less reactive than 99% white fuming nitric acid that has been diluted slightly?

Well yes it doesn't attacks stuff that good when pure, because for example metals get a passivation layer.
But I think fuming nitric acid is much much worse on skin, because it is such an extremely strong oxidizer! I mean just look what happens with gloves when putting azeotropic or fuming nitric acid on them. The glove with the fuming nitric will start to burn violently and the glove with the azeotropic nitric acid doesn't ;)




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Bedlasky
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[*] posted on 15-6-2020 at 07:17


Chemorg42: As Syn the Sizer said, red fuming nitric acid is more corrosive fue to dissolved NO2.

Tellurium: I tried dissolve copper wire and molybdenum powder in white fuming nitric acid and they are attacked only little bit. There was some NO2 formation, but only small amount. WFNA passivated these metals. But when I added small amount of water, vigorous reaction with cloudes of NO2 took place.




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[*] posted on 15-6-2020 at 07:35


Quote: Originally posted by Bedlasky  
Tellurium: I tried dissolve copper wire and molybdenum powder in white fuming nitric acid and they are attacked only little bit. There was some NO2 formation, but only small amount. WFNA passivated these metals. But when I added small amount of water, vigorous reaction with cloudes of NO2 took place.

Yes, thats exactly the passivation, that I'm talking about! This is caused by strong oxidizing properties, but I guess on skin exactly these oxidizing properties are the problem ;)

[Edited on 15-6-2020 by Tellurium]




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[*] posted on 15-6-2020 at 08:15


Yes, they are :D. As I said before, it burns like a hell.



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[*] posted on 15-6-2020 at 17:46


A little tip for dealing with H2O2 burns is to use hot water on the burn and I press on it with my fingernail. It seems to reduce the pain a bit and it can make the white "burn mark" (which I think it just tiny O2 bubbles under the skin) disappear much faster, I think it's b/c it speeds up blood flow to the area. It also does reduce the pain level a bit and I've never really gotten the same effect with cold water. My experience is with 35% and I too think it has a much faster reaction to skin than any acids (at least room temp acids).
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[*] posted on 15-6-2020 at 21:24


Quote: Originally posted by Bedlasky  
I never heard about 100% HNO3. White fuming nitric acid can exist in concentrations up to 99%, but it never be 100%. But it's less reactive than red fuming nitric acid which contain lots of NO2.


100 % HNO3 is quite possible, but not very popular. You can quite easily have "over 100 %" HNO3, in the sense of N2O5 rather than N2O4 dissolved in HNO3. This type of "nitric acid oleum" is one popular nitrating agent - more stable than pure N2O5 or N2O5 dissolved in nonpolar solvents, and better nitrating agent than 99 % HNO3. Often, it also contains phosphoric acid when it is produced simply by partially dehydrating nitric acid with P4O10 and phosphoric acid not separated. But you can produce clean HNO3/N2O5 solution as well.

As for precisely 100 % HNO3, note that 100 % crystals are the freezing point maximum, somewhere about -41,6...41,8 %. On slow freezing of near 100 % nitric acid, the growth of crystals would reject any dissolved H2O, N2O4 or N2O5 impurities into the mother liquor. Solid nitric acid, unlike all liquid forms, is reasonably stable to spontaneous decomposition. Which means you could store nitric acid as a solid and thaw as needed.
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[*] posted on 16-6-2020 at 05:32


Quote: Originally posted by chornedsnorkack  
Quote: Originally posted by Bedlasky  
I never heard about 100% HNO3. White fuming nitric acid can exist in concentrations up to 99%, but it never be 100%. But it's less reactive than red fuming nitric acid which contain lots of NO2.


100 % HNO3 is quite possible, but not very popular. You can quite easily have "over 100 %" HNO3, in the sense of N2O5 rather than N2O4 dissolved in HNO3. This type of "nitric acid oleum" is one popular nitrating agent - more stable than pure N2O5 or N2O5 dissolved in nonpolar solvents, and better nitrating agent than 99 % HNO3. Often, it also contains phosphoric acid when it is produced simply by partially dehydrating nitric acid with P4O10 and phosphoric acid not separated. But you can produce clean HNO3/N2O5 solution as well.

As for precisely 100 % HNO3, note that 100 % crystals are the freezing point maximum, somewhere about -41,6...41,8 %. On slow freezing of near 100 % nitric acid, the growth of crystals would reject any dissolved H2O, N2O4 or N2O5 impurities into the mother liquor. Solid nitric acid, unlike all liquid forms, is reasonably stable to spontaneous decomposition. Which means you could store nitric acid as a solid and thaw as needed.


That's really interesting! I never heard about this HNO3/N2O5 mixtures.




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