heptatrolytic - 17-4-2006 at 19:08
For Royal Water/Aqua Regia, (1:Nitric acid/3: HCl)
Would it be easier to just run a tube from the vessel containing H2SO4/Sodium Nitrate into a vessel containing the HCl, and just bubble the Nitric
Acid instead of setting up a distillation apparatus?
12AX7 - 17-4-2006 at 19:45
You'll need cooling to prevent evaporation, since HCl is volatile and HNO3 releases heat on dissolution, no? Otherwise I don't see why it wouldn't
work.
Tim
BromicAcid - 17-4-2006 at 19:55
In response to your question, no, that doesn't sound easier to me at all. Sounds like more things could go wrong then a simple distillation followed
by mixing.
thefips - 20-4-2006 at 06:17
I made Royal Water a few weeks ago. I took 1 part HNO3 (63%) and 3 parts HCl(aq) (~30%) and mixed them in a beaker. It worked very good, all the gold
i dropped in dissolved. You don´t need very concentrated acids.
Fleaker - 21-4-2006 at 10:39
No, concentrated acids aren't required at all, but they will speed up the dissolution of gold, which will readily dissolve in even cold aqua regia. As
Bromic said, there is no reason to bubble HCl gas into a nitric acid solution, none at all. Just simply mixing it in a 3.5 HCl to 1 HNO3 ratio will
give you the orange solution, no distillation needed. Remember to do it outside or away from anything you don't want rusted, the fumes will even
corrode stainless steel, and as always, avoid breathing it.
garage chemist - 21-4-2006 at 11:06
Also, don't store aqua regia, it slowly decomposes, producing gases like chlorine and nitrogen oxides. If stored in a sealed bottle it will eventually
explode. There once was an accident due to this.
Eclectic - 21-4-2006 at 15:40
Has anyone tried distilling 37% HCl and NaNO3? Does it produce useable aqua regia, or is the decomposition too severe? Does NaCl crysalize out due
to common ion effect?
woelen - 22-4-2006 at 14:31
Heating this liquid does not result in aqua regia being distilled, but instead you get lots of chlorine gas, ONCl and NOx.
You can use a mix of HCl and NaNO3 directly as a substitute for aqua regia. Powder the NaNO3 as good as possible, then add this to luke-warm
concentrated HCl. You'll get a white precipitate, which is mostly NaCl. Heat the liquid, until it becomes yellow, then let the solid settle at the
bottom and decant the clear liquid. This stuff still contains some Na(+) ions, but it perfectly works as aqua regia.
For each four moles of HCl you need one mole of NaNO3.
pyrochem - 24-4-2006 at 21:10
Wouldn't the main gas produced just be HCl? It's a gas at room temperature and comes out of solution easily.
12AX7 - 24-4-2006 at 22:44
Well, not really, considering how soluble it is.
I recall reading here it forms an azeotrope around 30% HCl, with a boiling point significantly above pure H2O's. Can't say it comes out of solution
easily if that happens.
Tim