I am interested in making saltpeter. However, I can’t get ahold of it without spending money. I wanted to settle for sodium nitrate, which is also a strong oxidizer. I need this stuff for chemistry experiments. I thought of taking Ammonium Nitrate fertilizer and dissolving it in water, then adding salt. Would the Ammo replace the sodium to make NaNO3 and NH4Cl2? Also, since I am pretty sure the sodium nitrate would be soluable, how would I get it out? Would the NH4Cl2 be insoluable?
Thanks a lot!
The chloride salts of ammonia and sodium are a lot less soluble than the nitrate salts, so you might be able to crystallize them out of a warm solution. It’d probably be tricky to do on a small scale.
Why in the world don’t you just buy saltpeter? It’s pretty cheap (less than $2 for a 4-oz bottle) at the grocery store down the street from me. It would take a hell of a lot more than $2 worth of effort and time to try to separate sodium nitrate from ammonium chloride.
Well, this former chemistry teacher wants to know what your intended uses of the product might be…
Your are correct, however, in recognizing that double replacement reactions are truly solubility/precipitate reactions (+1 for you). What you need is a good table of solubilities. I can tell you that all non-transitive metal nitrates are very soluble in water, sodium included. Many non-metallic chlorides are semi-soluble in water. So the question is, “How to precipitate out one compound and leave the other.”
Since you want the nitrate to be purified, as opposed to the chloride, you would rather it precipitate out first and filter it away. Since reducing temperature would precipitate out the chloride first, cooling the solution wouldn’t work. Your best bet would be changing the mole fraction of water in the solution to a point where the nitrate is not soluble but the chloride is. This would require finding a liquid that is a solvent for the chloride but not the nitrate and adding it slowly until the nitrate precipitates out. I imagine, with ammonium, you’d have to use something very non-polar, maybe benzine or perhaps toluene.
Or, you could try to add another ion to the solution that would definately precipitate out the chloride ion, while also precipitating out the remaining ammonium ion with the anion from the new addition. Can’t think of one though.
Either way, you’d need a good vacuum flask and Buchner funnel (please add umlaut over the u).
Perhaps you could just buy some salt peter…