# Tall beaker



## machiavelli976 (May 26, 2015)

A friend gave me some kind of pyrex bubblers . One has broken frit inside so I've decided to cut the useless top. That allowed me to test a nitric pin digestion with weak acid , high liquid column and almost sealed setup . Almost sealed because the lens used as tap is pretty heavy comparing with regular watch glasses of lab gear.
The brown fumes escaped are almost invisible , the space above liquid is only slight colored and removing the lens , huge brown fumes appear like from nowhere .
I guess this is the prove that nitric gas is absorbed and maybe it returns as acid leaking down inside the beaker walls. Maybe the much lower temperature of the glass at the top , helps the absorbtion of the brown fumes. 
I wish to test an even higher beaker but no one like desired I've found yet.


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## butcher (May 26, 2015)

Nitrous oxide (NO gas) fumes are colorless, when they get oxygen they form Nitrogen dioxide (NO2 gas).
NO gas basically not water soluble, NO2 gas is water soluble.
the concentration of the acid you use can make a big difference on which gas is mainly formed as the nitric attacks the metal, water or even excess water in your nitric can help keep these fumes in solution, where they can dissolve more metal, adding a little oxygen like a little hydrogen peroxide can also help to keep these fumes in solution where they will do more work.
2NO + O2 --> 2NO2
2NO2 + H2O --> HNO3
NO + NO3 + H2O2 (H2O) --> 2HNO3 (H2O)

These are not the only gasses of nitrogen formed we call NOx gas.


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## machiavelli976 (May 27, 2015)

butcher said:


> Nitrous oxide (NO gas) fumes are colorless, when they get oxygen they form Nitrogen dioxide (NO2 gas).
> NO gas basically not water soluble, NO2 gas is water soluble.



That makes sense , I've noticed if I remove the tap and put it back before brown fumes formed escape , a slight vacuum comes instantly , meaning the absorbtion of new NO2 occur (the beaker don't have any pouring groove ). Looks like something taller will work even better.

Thanks for the info , butcher !


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