Sciencemadness Discussion Board - Zinc Nitrate? lets hope...

Zinc Nitrate? lets hope...

Chemist514 - 1-7-2006 at 12:40

First try at making something for my collection that i have none of...
Bought 500 grams mossy zinc so I have my old zinc from dry cells surplus and 1litre of 15% nitric acid I dont have any use for as I am just starting out.. lets see.. 100 ml nitric acid in 600 ml beaker, ill add zinc untill no more will be acted upon, then filter small bits of paper i see from battery lining out with whatever else may have fell in there, and evaporate whats left to crystals... sounds ok to me. *nervous twitching*

The_Davster - 1-7-2006 at 13:11

Yeah, sounds good. You will end up with the hexahydrate upon evaporation. NOx will be given off, do this outside.

Keep in mind half of the nitrogen in your nitric acid will be lost as NO/NO2 as nitric is an oxidizing acid, so in the future when making nitrate salts it would be best to dissolve a metal oxide in nitric acid to conserve your nitric.

neutrino - 1-7-2006 at 14:39

Dissolving zinc in a strong acid produces nascent hydrogen. This is an extremely powerful reducing agent and will reduce some of the nitric acid to ammonia.

The specifics of this escape me at the moment. I remember a lengthy discussion in one of the JCE articles that was uploaded a few months ago to some FTP. It was:
Chemical of the Month: Nitric Acid
v61 n2 p174-76 Feb 1984.

I’ll upload the text when I get my hands on a copy of this article.

edit: Here is the necessary text from the article.

Quote:

In general, metals which are above hydrogen on the electromotive series yield H2, N2, NH3, NH2OH, or NO when treated with nitric acid. Metals which are below hydrogen in the electro-motive series tend to give NO or NO2.

Zn + 2H+ --> Zn2+ + H2
(25%)

3Zn + 8H+ + 2NO3- --> 3Zn2+ + 4H2O + 2NO
(dilute)

4Zn + NO3- + 10H+ --> 4Zn2+ + 3H2O + NH4+
(dilute)

6Zn + 16H+ + 2NO3- --> 6Zn2+ + 4H2O + 2NH3OH+
(concentrated)

[Edited on 1-7-2006 by neutrino]

[Edited on 2-7-2006 by neutrino]

The_Davster - 1-7-2006 at 15:24

Ok, yeah, diluted nitric will react with zinc to make the nascent hydrogen, concentrated will give the nitrogen oxides. I just tried it.

So if you are using your 15% acid you will end up with ammonium nitrate contaminants(EDIT: and I guess hydroxylammonium nitrate), either use concentrated nitric or if that is not possible, make Zinc oxide, hydroxide or carbonate first, and dissolve that in your 15% nitric acid.

[Edited on 1-7-2006 by rogue chemist]

Chemist514 - 1-7-2006 at 15:41

Ah interesting i seem to be having the same problem i had with ammonium nitrate "cleaning", i had one heck of a time drying it! seems same issue here...
Ill try to get concentrated acid, but i was hoping this would have been of some use.
Guess ill can the batch of iron nitrate i was hoping for too.. too much to go wrong even here.
Say if i have ALOT of 15% can i concentrate this acid by just boiling off excess water or is the acetic acid issue going to come up? ( can buy 4 litres at a time pretty cheap..)

neutrino - 1-7-2006 at 16:42

Sorry, I mislabeled the last equation. It occurs with concentrated acid, not dilute acid. I just fixed it in the post above.

With the equation fixed, we see that concentrated acid is even worse than the dilute stuff. So don't even bother with that.

The best way I can see to make zinc nitrate would be by a single replacement reaction. First dissolve some copper with your nitric acid to form a solution of copper (II) nitrate. Then add some zinc to displace the copper:

Cu2+(aq) + Zn(s) --> Cu(s) + Zn2+(aq)

The reaction will near completeness as the blue color of hydrated Cu2+ ions fades and only zinc nitrate is left in solution.

If you have some nitrates lying around, you could work your way to something like copper nitrate without wasting precious nitric acid.

[Edited on 2-7-2006 by neutrino]

12AX7 - 1-7-2006 at 20:40

Ooh, Cu to Zn. Better still, hook up a few as gravity cells and use the power for something instead of short-circuiting it, although the reaction would have a nice pace to it!

Tim

Back to basics...

Chemist514 - 2-7-2006 at 09:08

Well, that WAS much fun.. but before i end up wasting my chems with idle amusments (I must say copper in nitric acid REALLY is amazing to watch though i think canadian pennies have something IN them nitric acid likes even more then copper cause i got a hollow penny.)
I will search the threads for some hint at making my nitric acid stronger and go back to learning basics as thats what all this is about.. ill keep watching you peeps in the meantime while stamp collecting chemicals...
All the very best to you!

unionised - 3-7-2006 at 12:24

I wonder if you have thought of disolving the zinc in NaOH (which is easy to get OTC). Acidifying it slightly with any cheap acid you can get (rather than nitric which isn't that common) to precipitate Zn(OH)2 and disolving that in HNO3. Less wasted HNO3 and less lung damage (only a bit less if you aren't careful with the NaOH fumes)

Odd!

According to Vogel's organic book you can activate Zn by washing with NaOH (10-15% Hot) until it reacts vigorously. OTOH I just tried it with hot NaOH (10% Boiling) and nothing happened. My Zn is sheet from a battery (and I do know the difference between Zn/C cells and alkaline Mn etc- the stuff really is Zn). Does the particle size really make that much odds?

[Edited on 3-7-2006 by unionised]

Chemist514 - 10-7-2006 at 21:37

By chance i saw a store that sold paint so i figured id scope it out for chems, whoa! they sell stuff to make your OWN paint... bought zinc oxide, 1 lb.

Ok here goes... oh that goes into solution so much cleaner. (zinc oxide in nitric acid 15%)
msds says zinc nitrate can explode if heated... thats bad.
Ill take out most of the water, not sure what ill do after that... guess wait it out.

No nasty brown smoke... thats a plus. wink.

neutrino - 10-7-2006 at 21:54

An MSDS saying that something can explode if heated means that in an absolute worst case scenerio where hundreds of tons of the material are engulfed in a hot fire for a prelonged period of time, a small amount could conceivably explode. When working with small quantities these warnings are generally not so relevant. Use common sense, work with reasonably small amounts, and you'll be fine.

I know that zinc chloride is very hygroscopic and difficult to dry. I imagine that the nitrate isn't too different.

woelen - 11-7-2006 at 01:21

Drying the nitrate by heating does not work. I did the same experiment a few years ago. When you boil down the liquid, first you get a syruppy liquid, which does not nicely crystallize. On further heating, the liquid starts to evolve brown gas, and O2/NO/NO2 and water are released. What remains is a white solid, which does not dissolve in water as a clear solution. I think that the white solid is a basic zinc nitrate, or even just zinc oxide.

You might be more succesful, if you heat until you get the syruppy liquid and then let it cool down and dry very slowly. This stuff then, however, will contain a lot of free acid. I did that with nickel nitrate made from HNO3 and dutch pre-euro coins (which were made of 99.5% nickel) and the solid I obtained still fumes a little, when exposed to humid air.

Chemist514 - 11-7-2006 at 07:11

Ok... I went a little slower this time and boiled most of the water out, then I got tired so I gave up and went to bed. This morning I looked in the beaker and its still got liquid in the crystals BUT they are long thin clear crystals.. I had dissolved zinc oxide untill no more would go into solution, does that not mean that most if not all the nitric acid was involved in the reaction? oh and I didnt see any sign of that brown gas this time. alot last time. lol

Rosco Bodine - 16-7-2006 at 08:50

Alternately ....

You could just use fertilizer grade zinc sulfate , make a hot solution and mix with hot sodium bicarbonate solution to precipitate zinc carbonate , filter and rinse .
Then add the zinc carbonate in portions to a boiling solution of ammonium nitrate until evolution of ammonia and carbon dioxide ceases and a clear solution of zinc nitrate results on long boiling . Cooling and evaporation
gets you crystals of zinc nitrate ....with no acids nor zinc metal required .