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Sulaiman
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[*] posted on 16-9-2016 at 13:58


I noticed on the nitrite Wikipedia page

"Sodium nitrite is made industrially by passing "nitrous fumes" into aqueous sodium hydroxide or sodium carbonate solution"

so next time I need to get rid of NOx fumes i know what to do :)



CAUTION : Hobby Chemist, not Professional or even Amateur
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aga
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[*] posted on 17-9-2016 at 08:28


Hmm. Tried cold NaNO2 solution with both HCl and H2SO4 and just got some more brown gas.

There *may* have been a faint 1mm deep ring of blue floating on top of the liquid for a second, but that could have been a trick of the light.



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aga
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[*] posted on 26-11-2016 at 02:44


After all the messing about, i discovered today that i simply did not know how to use starch-iodide papers properly.

Turns out that they need to be wetted with a 1% HCl solution first.

http://chestofbooks.com/science/chemistry/Processes-Dye-Chem...

Doing that with one of the remaining papers (wasted most of them) it went dark blue with 1 drop of a very dilute NaNO2 solution.

The nitrite and the papers were both actually OK from the beginning !

Edit:

If i'd understood what Magpie said earlier, i'd have known sooner.

[Edited on 26-11-2016 by aga]



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S.C. Wack
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[*] posted on 26-11-2016 at 06:30


In the usual usage the solution to be tested is already acidic and may even need to be diluted with water before dropping it on the paper.



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aga
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[*] posted on 26-11-2016 at 11:06


Quote: Originally posted by S.C. Wack  
In the usual usage the solution to be tested is already acidic

Thank you for that info.

So obvious now i think about it, yet i've been hung up on this for months !

In retrospect, i think i went wrong by thinking of an 'indicator' as something magical, and not just another a chemical reaction.



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[*] posted on 6-3-2017 at 20:19
Sodium Iodide?

Can this preparation be done with naoh instead of koh, or is potassium necessary?
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