acetone
Harmless
Posts: 35
Registered: 13-5-2013
Member Is Offline
Mood: No Mood
|
|
Concentrating nitric acid
Is it possible to concentrate the 68 percent azeotrope of nitric acid and water by blowing nitrogen dioxide gas into it. Meaning that nitrogen dioxide
combines with water to make nitric acid. Can it work?
|
|
|
ElectroWin
Hazard to Others
Posts: 224
Registered: 5-3-2011
Member Is Offline
Mood: No Mood
|
|
yes, but this doesn't give you pure nitric acid. as far as i know, some of the NO2 dissolves in the solution turning it reddish brown. and there are
temperature-dependent side reactions making N2O4.
but as i understand, the reactions are:
3 NO2 + H2O --> 2 HNO3 + NO
the NO may be removed by bubbling air into the solution, until it becomes clear.
2 NO + O2 --> NO2
[Edited on 2013-6-16 by ElectroWin]
|
|
|
vmelkon
National Hazard
Posts: 669
Registered: 25-11-2011
Location: Canada
Member Is Offline
Mood: autoerotic asphyxiation
|
|
Quote: Originally posted by ElectroWin  |
the NO may be removed by bubbling air into the solution, until it becomes clear.
2 NO + O2 --> NO2
[Edited on 2013-6-16 by ElectroWin] |
If you bubble air into it, the NO2 formed would color the liquid red.
NO is colorless.
|
|
|
franklyn
International Hazard
Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline
Mood: No Mood
|
|
You obtain red fuming nitric acid
67 % white nitric acid
18 HNO3 + 31 H20
treated with NO2
31 H20 + 62 NO2 => 31 HNO3 + 31 HONO
becomes a mixture of 68 % nitric acid + 32 % nitrous acid
18 HNO3 + 31 HNO3 + 31 HONO
aeration will eventually oxidize the nitrous acid into nitric acid.
Becoming fuming white nitric acid ,
2 HONO + O2 => 2 HNO3
From here read below => www.slideshare.net/LisaPluis/presentation-nitric-acid
~ 68 % nitric acid can be further concentrated by passing a mixture of nitrogen
dioxide and air through the 68 % aqueous solution. This solution can be further
concentrated by distilling it with concentrated sulphuric acid (or Mg(NO3)2 )
under reduced pressure. By this method nitric acid of 98% concentration can be
obtained. If the 98% acid is cooled to -42 ºC, then pure nitric acid of 100%
concentration crystallises out as colourless crystals.
.
|
|
|
acetone
Harmless
Posts: 35
Registered: 13-5-2013
Member Is Offline
Mood: No Mood
|
|
Thank you for your replies.
|
|
|
acetone
Harmless
Posts: 35
Registered: 13-5-2013
Member Is Offline
Mood: No Mood
|
|
I have one more question. What is this "national hazard", "international hazard", "harmless" under people's user names? What does it mean?
|
|
|
Hockeydemon
Hazard to Others
Posts: 218
Registered: 25-2-2013
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by acetone | | I have one more question. What is this "national hazard", "international hazard", "harmless" under people's user names? What does it mean?
|
I'm not positive on the exact posts required for the titles, but I believe it is
1-49 posts = harmless
50-99 posts = hazard to self
100-199 posts = hazard to others
200-something = national hazard
And so on...
Though if you consistently discuss 'dangerous' things then a mod might just bump your title up regardless of your post count.
|
|
|
Finnnicus
Hazard to Others
Posts: 342
Registered: 22-3-2013
Member Is Offline
|
|
That doesn't happen^ But special titles are awarded sometimes. See Andershoveland and Thedavester.
|
|
|
DrSchnufflez
Hazard to Others
Posts: 114
Registered: 22-1-2013
Location: Australia
Member Is Offline
Mood: No Mood
|
|
Back to the original topic. The most conventional way of concentrating azeotropic nitric acid is mixing with an equal volume of conc sulphuric acid
and distilling off the now red fuming nitric acid in an all glass ditillation apparatus. 
|
|
|
Finnnicus
Hazard to Others
Posts: 342
Registered: 22-3-2013
Member Is Offline
|
|
I got a question (kinda).
Can some one please explain about vacuum distillation of HNO3? Heard it was commonish.
|
|
|
DrSchnufflez
Hazard to Others
Posts: 114
Registered: 22-1-2013
Location: Australia
Member Is Offline
Mood: No Mood
|
|
The purpose of vac distilling nitric acid is to lower the boiling point so as the nitric acid does not decompose into NOx as much as an atmospheric
pressure distillation would do. By doing this it's possible to get nearly white fuming nitric acid instead of the more usual red fuming nitric acid.
|
|
|
Finnnicus
Hazard to Others
Posts: 342
Registered: 22-3-2013
Member Is Offline
|
|
Hmm. So to lessen decomposition. Know where I can find HNO3's boiling points under various pressures?
|
|
|
Hockeydemon
Hazard to Others
Posts: 218
Registered: 25-2-2013
Member Is Offline
Mood: No Mood
|
|
You should just be able to find a pressure vs temperature graph on google for HNO3, but I would just read through this thread if you're interested in making WFNA.
|
|
|
acetone
Harmless
Posts: 35
Registered: 13-5-2013
Member Is Offline
Mood: No Mood
|
|
Testing to see if signature appears.
The measure of a man is what he does with power.
-Plato
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
