Sciencemadness Discussion Board

NaNO3 + Al + H2O

binaryclock - 18-4-2013 at 21:16

So today I decided I'm going to try to filter out the NaNO3 from my drain cleaner.

However when I added water to the NaNO3 mixture and the Al shavings, I smelled a faint ammonia smell. Reading about it, it seems that the Al reacts with the nitrate to give off an ammonia gas. After paper filtration I still went ahead and boiled the mixture down to form crystals.

Question is, what do I have crystals of right now? :P Aluminum nitrate?

Thanks for the help..

elementcollector1 - 18-4-2013 at 21:26

2NaOH + 2Al + 2H2O → 3H2 + 2NaAlO2
That's the actual reaction between aluminum and sodium hydroxide,
Quote:
The sodium nitrate "absorbs" the hydrogen, reducing the fire and explosion hazard posed by free hydrogen gas. Hydrogen combines with the nitrate ion, producing ammonia, which also decomposes organic material although not as aggressively as lye does. The reaction is: 2NO3− + 9H2 → 2NH3 + 6H2O.

And that's the reaction between the produced hydrogen and the nitrate ion, yielding the smell of ammonia.
As for product, you likely have NaAlO2 (sodium aluminate), leftover hydroxide and nitrate, etc.

binaryclock - 18-4-2013 at 22:05

Hmm interesting. Thanks for the reply.