I just made silver nitrate by dissolving silver in HNO3. Right now I have it in my hood, with my hood running, because I don't know what to wash it
with. Is there any COMMON lab reagent (ethanol, methanol, acetone, toluene, etc.) that I can wash it with without dissolving it?Retard-3000 - 12-10-2011 at 11:52
Looks like cold acetone is your best bet ScienceHideout - 12-10-2011 at 11:58
Hmm... so if I wash with 10mL of acetone... .035 will dissolve... maybe afterwards I can leave my acetone to evaporate and get more AgNO3... Thanks a
lot!
[Edited on 12-10-2011 by ScienceHideout]
[Edited on 12-10-2011 by ScienceHideout]Retard-3000 - 12-10-2011 at 12:08
Well the info on the page says 1000g of acetone will dissolve 3.5g AgNO3 at (14C). Because it's in grams and the density of acetone is 0.791g it works
out that 1264ml of acetone will dissolve 3.5g, you'd be better off washing the silver nitrate at an even lower temperature. You'll only need to use a
small amount such as 50ml anyway and even then the solubility in 50ml of acetone is 0.13g. If you're still worried about losing 0.13g you can put the
acetone in the freezer for a few hours (acetone has a melting point of -93C so won't freeze) and that'll also decrease the solubility dramatically or
use a smaller amount such as 10-20ml
[Edited on 12-10-2011 by Retard-3000]Lambda-Eyde - 12-10-2011 at 14:20
Uh, why would you want to wash it? What impurities do you want to get rid of?hkparker - 12-10-2011 at 15:21
Uh, why would you want to wash it? What impurities do you want to get rid of?
That. Was your silver impure, and now you have copper nitrate mixed in? If not then you should just dry it.barley81 - 12-10-2011 at 15:43
Here is a whole thread on purifying silver nitrate. It was mentioned to heat silver nitrate to decompose the copper nitrate, dissolve, filter, and
if it's still blue, repeat.
[Edited on 12-10-2011 by barley81]ScienceHideout - 12-10-2011 at 16:32
I want to get rid of the nitric acid... there is no CuNO3 cuz I used pure silver. I just want to clean the silver nitrate without losing anything but
left over acid.barley81 - 12-10-2011 at 16:38
In that case, dessicating over NaOH/Ca(OH)<sub>2</sub>/CaO should work to remove adhering acid since nitric acid is volatile, though there
may be some acid trapped within the crystals.ScienceHideout - 12-10-2011 at 16:41
That sounds good- I should try... Sure glad aluminum isn't reactive with nitric acid- or my fume hood duct would've already been gone! hkparker - 12-10-2011 at 17:29
Dessicate over NaOH, breaking up the crystals as necessary.Endimion17 - 13-10-2011 at 05:29
I had the same problem this summer. Somehow I got hold of a small amount of silver nitrate at least 50 years old. It was actually - silverish.
So without removing anything from the bottle, I've added some conc. nitric acid to barely cover the crystals and started crushing them. Next day I
found no more silver, just silver nitrate and the concentrated solution of it in the acid. Neat.
I've tried to drive off the acid by heating, but the fumes are just too corrosive and ruining any equipment wasn't an option, so I've made a
desiccator using a jar and a mixture of NaOH, Ca(OH)<sub>2</sub> and silicagel. I've covered the unscrewed bottle with a piece of tissue
(celulose breaks apart quickly in such environment, so I had to replace it now and then; it's better to use something else) and placed it on a piece
of paper in the jar, to avoid the glass bottle touching NaOH.
Then I've simply put the jar in a dark place, occasionally replacing the tissue and swirling the desiccating mixture.
It took like 2 months in a cool and dark place, but I've got really white/transparent, dry crystals.
I could've put it in a warm place, but didn't want to.
The bottle is now wrapped in aluminium foil to avoid light exposure.
NaOH+lime mixture has a specific name which I don't know the english translation of. We call it "natronsko vapno". It can be used to decarboxylate
some organic chemicals (it gives methane if sodium acetate is heated with it), but it's great for dessicating because it won't liquefy, therefore its
available surface area doesn't change appreciably. It sucks in corrosive inorganic volatiles such as HX and nitric acid, trapping them in the form of
halides or nitrates.
One avoidable problem is that it can etch glass, so use it in a plastic container.
It's also great when mixed with cobalt-doped silicagel because its surface area becomes readily available, and the gel turning pink means it's really
the time to replace it.
