smaerd
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Nuetralizing Conc. Nitric Acid
Hey all, I figured I'd make this thread for two reasons one as sort of a lesson and two to start maybe a discussion.
So I'm moving in the near future and realized "Oh shit I do not want to drive with concentrated nitric acid in my car and store it at my new living
arrangement". I made it to create bismuth nitrates (sub nitrates) but never got around too it. So young experimenters, if you are lazy or easily
distracted consider the hazardous reagents before you prepare them at any sizeable quantity. You'll probably be moving either to college, or your
parents new job, or grad school, you never know.
Anyways, here's how I went about quenching/neutralizing the HNO3. I diluted the sample from ~125mL to ~200mL very quickly with ice cold water. It
hissed furiously. I added ice cubes and chucked ~5g of solid NaOH. I waited then repeated this maybe 5 times until the solution stopped
hissing/bumping on addition of NaOH. Then I started adding ~10g of NaOH at a time. I have to say I really don't like using this method, even when done
outdoors as carefully as possible I'm not sure if I exposed my lungs to the stuff or not :/, and the splashes were not controlled.
My thinking was by adding solid NaOH to the ice ontop I could delay the vigorous exotherm of nuetralization long enough to clear my way from the
erlenmeyer. That's probably dumb in retrospect.
Here's where I'm a bit mystified/confused currently. Say my nitric acid was 70% (more like 90% the stuff was fuming). Thats around 18M, or ~ 2.0 mols
per 125mL. I've added more than 80g of NaOH and now I have the issue that it appears the NaOH is insoluble in the solution even after significant
dilution via ice additions.
Anyone have any advice on how to go about this for a future experimenter. Or how I should procede from where I'm at now as *safely* as possible?
Edit-
Also how would I know if I should go to the hospital for exposure? I have a mild cough which developed 4 hours after being near the solution/adding
ice/NaOH.
[Edited on 8-7-2015 by smaerd]
[Edited on 8-7-2015 by smaerd]
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smaerd
International Hazard
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Just checked the pH it's finally "strongly basic" so I can just let the solutions evap away safely no problems.
So yea this method works but its pretty unsafe. I don't recommend it.
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Metacelsus
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Dilute, add ammonia, spread on garden . . .
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unionised
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Dilute by pouring onto ice cubes. Neutralise by pouring into lots of limestone.
Make sure the bucket is big enough for the foaming.
And finally, just to upset the environmentalists with no sense of proportion, chuck it in the river.
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j_sum1
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I would put it in a sep funnel and drip slowly into a large bucket of dilute base. (Ammonia is a good idea). Then walk away and come back when it is
finished.
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Varmint
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Wow, what a waste.
I would have at the very minimum spent the time to make something useful from it like copper nitrate.
Easy enough to turn back into HNO3, and pretty enough to have sitting around as a decoration/curio in the meantime.
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smaerd
International Hazard
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@Cheddite & J-sum1 - For some reason ammonia didn't cross my mind. I even have a bottle of the stuff. Oh well.
@unionised - I'm just going to store it as the nitrate salt lol. No river pollution for me  .
@Varmint - Yea it probably does seem like a waste. Thing is though, sodium nitrate to nitric acid isn't hard to do either. Considering where I'll be
living, I won't be messing with reagents like that for a long time. For better and for worse.
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Oscilllator
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smaerd please tell me you poured the nitric acid into the water, and not the other way round...
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smaerd
International Hazard
Posts: 1262
Registered: 23-1-2010
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Oscillator I poured the water into the nitric! 
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