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 - 16-6-2013 at 14:21
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 - 16-6-2013 at 21:09
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 - 17-6-2013 at 01:43
Thank you for your replies.acetone - 17-6-2013 at 01:45
I have one more question. What is this "national hazard", "international hazard", "harmless" under people's user names? What does it mean?Hockeydemon - 17-6-2013 at 02:00
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 - 17-6-2013 at 02:12
That doesn't happen^ But special titles are awarded sometimes. See Andershoveland and Thedavester.DrSchnufflez - 17-6-2013 at 02:16
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 - 17-6-2013 at 03:21
I got a question (kinda).
Can some one please explain about vacuum distillation of HNO3? Heard it was commonish.DrSchnufflez - 17-6-2013 at 03:40
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 - 17-6-2013 at 03:57
Hmm. So to lessen decomposition. Know where I can find HNO3's boiling points under various pressures?Hockeydemon - 17-6-2013 at 04:32
Hmm. So to lessen decomposition. Know where I can find HNO3's boiling points under various pressures?
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 - 17-6-2013 at 14:20
