Sciencemadness Discussion Board

What just happened?

OneEyedPyro - 4-12-2015 at 08:11

Yesterday I made a batch of NC with AN/H₂SO₄ and pure medical grade cotton balls.

After plenty of washing with tap water I placed it in a hot bicarb solution and began to work it around with my bare hands, almost no reaction occured as it was already quite neutral from the previous washes, after a short while of kneading I was interrupted by a phone call so I dried my hands off a bit on my pants and picked up the phone, as I was walking around I could smell a very faint ammonia smell but couldn't find the source, eventually I realized the smell was coming from my hands so I went back to the NC only to find it producing bubbles of ammonia gas and quite rapidly I might add :o

So what was going on there? The only thing I could guess was something to do with the ammonium sulfate and sodium bicarbonate reacting but I find this unlikely due to how well it was washed before being dropped in the bicarb solution not to mention that one would expect ammonium carbonate and sodium sulfate rather than ammonia gas.

[Edited on 4-12-2015 by OneEyedPyro]

kecskesajt - 4-12-2015 at 12:27

(NH4)2SO4 reacts with NaHCO3 to form ammonium carbonate.
(NH4)2CO3 decomposes in hot water, and also sublimates.

shivam - 6-12-2015 at 00:23

It's clear that the cotton balls might have absorbed a good amount of ammonium sulfate while nitrating
Which can be hard to wash out. For thorough washing, It'd help if you tore apart cotton into little bits and wash it.
Otherwise the ammonium sulfate traces will react with sodium bicarbonate solution to form ammonium carbonate
Now, you used hot solution and ammonium carbonate readily decomposes in hot solutions giving off ammonia

2NaHCO3 + (NH4)2SO4 --> NH4)2CO3 + Na2SO4 + H2O + CO2

(NH4)2CO3 --> 2NH3 + H2O + CO2

Generation of ammonia usually won't be a problem when cold water is used
moreover, after it's dried, all the ammonia smell is gonna go away anyway..