Sciencemadness Discussion Board - Is there a way to dissolve silver without HNO3?

Is there a way to dissolve silver without HNO3?

Random - 25-11-2013 at 09:52

I can make aqua regia but it will form insoluble silver chloride. No access to nitric though. Any alternative ways?

DraconicAcid - 25-11-2013 at 10:03

I suspect cyanide and oxygen would dissolve it nicely, but if you can't get nitric acid, then you probably can't get cyanide (and seriously, who wants to work with cyanide?).

If you can make aqua regia, I suspect you're mixing a nitrate with hydrochloric acid. Can you mix the nitrate with sulphuric acid? Silver sulphate is more soluble than the chloride.

UnintentionalChaos - 25-11-2013 at 10:22

Quote: Originally posted by DraconicAcid

Silver sulphate is more soluble than the chloride.

About 7.9g/L at room temperature. I would strongly hesitate to call that soluble.

woelen - 25-11-2013 at 10:38

If you have access to nitrates and sulphuric acid, then why not distill some to make HNO3 yourself? You should not make fuming HNO3, making a 60% solution should do the trick. Just add water and KNO3 to H2SO4 and boil off the liquid at 120 C or so.

PHILOU Zrealone - 25-11-2013 at 11:35

If you don't have HNO3...then

Perchloric acid. Silver perchlorate is soluble.

Concentrated (not anhydrous) acetic acid alone with air (or maybe with some H2O2). Silver acetate is soluble and acetic acid dissolves the oxyde layer.

NH4OH alone with air (or maybe with some H2O2). NH3 complexate Ag2O and dissolve the oxyde layer

Maybe NH4Cl with HCl or NH4Cl with NH4OH. AgCl is soluble in NH4OH and complexate.

bfesser - 25-11-2013 at 11:44

Amos Backstrom, I strongly disagree with your statement about "making good nitric acid." It's quite simple, and an apparatus can be improvised from basic kit—a florence flask, a glass tube, and a collection vessel submerged in ice are more than satisfactory. A little care and forethought is required to carry out the procedure safely, but it's by no means difficult to obtain a product of sufficient purity.

woelen - 25-11-2013 at 12:36

Distilling nitric acid requires an all glass apparatus with good seals. It is making the seals which make the setup difficult if you don't have a distillation setup with ground glass joints. Using rubber or cork for joining tubes to each other is a no go with hot nitric acid vapors.

Dilute HClO4 does not dissolve silver. I can imagine though that dilute HClO4, mixed with H2O2 will do the job. If OP does not have HNO3, then I also strongly doubt he has HClO4.

Random - 25-11-2013 at 12:50

Actually the only strong acid I have access to is HCl. So from all these options ammonia would be the best for me. If silver chloride complexes with ammonia maybe I could make a soluble acetate from that complex and vinegar?

Silver and ammonia would have to get used fast though, I don't want that stuff exploding on me.

Now on obtaining silver chloride, would aqua regia work or would it just passivate my silver piece?

I was also thinking of electrolysis, maybe in vinegar?

Also I could make aqua regia with ammonium nitrate already, but I'm not sure if that is a safe option at all.

[Edited on 25-11-2013 by Random]

deltaH - 25-11-2013 at 14:18

Random, some food for thought:

You may be able to purchase sulfamic acid OTC as it is used as a descaler (check MSDS of brands available to you for composition confirmation). Silver sulfamate appears to be fairly soluble, for example, see this silver sulfamate plating solution patent:

http://www.google.com/patents/US4279708

I couldn't find an exact solubility value for you, but that patent is somewhat indicative as they have an example using 60g/l (example 4).

You would still need an oxidant for the dissolution. I'm stuck on that as silver is an effective peroxide decomposition catalyst, so that may not be a viable means and I cannot think of a good non-nitrate alternative. I also don't think peroxide and sulfamate can be safely paired.

Be aware that an electrochemical oxidation may not be straightforward. For starters, you could have your silver simply electroplating from anode to cathode if the silver ions are not isolated between anolyte and catholyte

On that note, salt bridges can be loads of chemistry fun. Perhaps experiment with preparing concentrated xanthan gum solutions using alkaline media and then gelling by mixing in concentrated sulfamic acid? I bought xantham gum from a health food shop for dirt cheap.

In summary, the best non-nitrate suggestion for dissolving silver I can come up with would be some kind of electrochemical oxidation approach using sulfamic acid and where you have isolated anolyte from catholyte.

[Edited on 25-11-2013 by deltaH]

bfesser - 25-11-2013 at 14:35

Amos Backstrom, I understood what you meant. I disagree. For preparing AgNO3, 50–60% HNO3(aq) should be just fine. If it's too concentrated, the silver will dissolve slowly, if appreciably (passivation, limited solubility, etc.). Preparation of nitric acid and it's use in preparing silver nitrate is one of those topics which has been discussed ad nauseam. I suggest you try searching the fora and reading through what's already been written on the subject before asking more questions. I think you'll find that all of your questions have already been answered.

[edit] <a href="viewthread.php?tid=25328">Silver Nitrate Synthesis</a>

[Edited on 25.11.13 by bfesser]

clearly_not_atara - 9-6-2014 at 02:08

http://anonym.to/https://answers.yahoo.com/question/index?qi...

diammine silver (I) chloride. AgCl (s) + 2NH3 (aq) --> Ag(NH3)2+ (aq) + Cl- (aq)

and I did in fact link yahoo! answers. in my defense i just remembered the complex name diamminesilver (I) and googled it.

phlogiston - 9-6-2014 at 13:46

Alternatively, you can dissolve the silver chloride in sodium thiosulphate solution.

Here is an interesting overview of solubilities:
http://www.saltlakemetals.com/Solubility_Of_Silver_Chloride....

A -long- time ago, when had no acces to nitric acid, I prepared a small sample of lead nitrate by dissolving metallic lead in molten ammonium nitrate. Perhaps the same works with silver, but do study the dangers of melting ammonium nitrate before you consider this (especially if you were to try this on more than a very small scale).

Paddywhacker - 10-6-2014 at 03:58

Silver will dissolve in liquid mercury, and also in molten copper or gold.

aga - 10-6-2014 at 13:47

Quote: Originally posted by woelen

I can imagine though that dilute HClO4, mixed with H2O2 will do the job

Is that pirahna solution on steroids ?!?!

woelen - 12-6-2014 at 03:25

Dilute HClO4 with H2O2 is not energetic or explosive at all. It is a mild oxidant. Dilute HClO4 is not oxidizing at all. I have done experiments with boiling 60% HClO4 and this liquid is not capable of oxidizing iodide to iodine or sulphur dioxide to sulfate. Zinc does dissolve in this, but only with formation of hydrogen gas (the acid part is the oxidizer, not the perchlorate part).

Piranha solution only is formed with nearly anhydrous conditions, i.e. conc. sulphuric acid with highly concentrated H2O2. It is a misconception to think of dilute acids with H2O2 as piranha solution.

quantumcorespacealchemyst - 6-2-2015 at 13:16

How about H2SO4 with KNO3 and Sodium acetate?

blogfast25 - 6-2-2015 at 13:23

Quote: Originally posted by quantumcorespacealchemyst

How about H2SO4 with KNO3 and Sodium acetate?

That would probably work but I don't see the point to the acetate.

The solubility limit of Ag2SO4 will reached regardless of acetate ions being present.

nezza - 7-2-2015 at 00:56

Concentrated sulphuric acid with heat will dissolve silver. For dilute acids an oxidising agent is required. Dilute sulphuric acid with hydrogen peroxide should dissolve silver. Nitric acid is by far the easiest way to get silver into solution though.

quantumcorespacealchemyst - 9-2-2015 at 01:51

Will the H2SO4 turn to 4K2SO4 with the NO3- going to Ag+ with the H+ going to H2 gases? I don't understand about the solubility limit of Ag2SO4 being reached. With the acetate, I was/am wondering about claiming AgOOCH3.

does KMnO4 + H2SO4 + Acetate/Acetic Acid destroy the Acetate ion. I am wondering about this for Ag, preferably from shot form (also Au and Hg {I read KMnO4 and H2SO4 dissolves gold but no salt is formable due to the instability of gold sulfates [on a refining forum]. I was unsuccessful so far, and have yet to test stronger acid and/or oleum})

clearly_not_atara - 4-5-2016 at 20:08

I can get to diamminesilver nitrate: EDIT -- all the way to silver nitrate, see bottom.

Silver sulfate + ammonia + Ca(NO3)2 (in water) >> CaSO4 (s) + Ag(NH3)2+ (aq) + NO3- (aq)

I don't have any idea how to get AgNO3*2NH3 to turn back into AgNO3. Heating will almost surely result in the reduction of silver and possibly explosive decomposition of the nitrogen compounds.

One possibility is to add silver (II) oxide to decompose ammonia. This is usually produced, again, from silver (I) solutions.

You can probably prepare some silver salts from this solution -- excess acid should break the Ag-N bond. Acetic acid will precipitate silver acetate, which can be used to make acetic anhydride. Boric acid should give silver borate. Toluenesulfonic acid, the tosylate.

EDIT: this paper says that diamminesilver slowly decomposes in warm solutions to liberate ammonia gas:

http://pubs.rsc.org/en/content/articlelanding/1975/an/an9750...

[Edited on 5-5-2016 by clearly_not_atara]

Sulaiman - 4-5-2016 at 22:08

getting silver into an aqueous solution ... for what purpose ?

silver nitrate is a useful reagent, a precursor to many silver compounds which themselves are mostly insoluble.
So if a route is available for you I think that it is worth the effort to make silver nitrate.

ionic and colloidal silver solutions can be made by electrolysis of distilled water with silver electrodes.
ionic up to 20 ppm so not 'soluble' by any common definition

notes:
Silver nitrate stains work surfaces and skin and can melt your corneas,
wear goggles & gloves (silver nitrate seems to go through latex gloves)
or, I use goggles and no gloves and rinse my hands with sodium thiosulphate solution before exposing to any sunlight.
I also used sodium thiosulphate to minimise any silver nitrate stains when I used the kitchen.

many silver compounds are light sensitive - especially when impure.

EDIT: if you do not have sodium thiosulphate do not do silver chemistry where stains are a problem !

[Edited on 5-5-2016 by Sulaiman]

macckone - 4-5-2016 at 23:26

Silver nitrate is not known to 'melt corneas'.
In fact solutions of silver nitrate are used as eye drops in newborns.
Any salt directly in the eye will be unpleasant unless diluted.
The most dangerous chemicals for your eyes are still strong acids and
bases. However brake cleaner will eat contact lenses and that can also
be unpleasant.

Sulaiman - 5-5-2016 at 04:36

1% silver nitrate used as Credé's Prophylaxis for newborns is, I believe, immediately followed by saline rinse,
converting caustic silver nitrate to silver chloride.
DO NOT GET SILVER NITRATE IN YOUR EYES, EVEN A TINY BIT.

clearly_not_atara - 5-5-2016 at 08:31

ALWAYS wear eye protection when doing any chemistry. This shouldn't be a question, even if the reaction is just salt metathesis.

AJKOER - 8-8-2016 at 04:59

Try microwaving a mix of elemental silver (or Sterling silver which is Ag mixed with Cu) with 3% H2O2, 5% acetic acid (vinegar) and a very small amount of sea salt (which acts initially as an electrolyte for this electrochemical based dissolution reaction) to form a dilute solution of soluble silver acetate (and some copper salts with Sterling silver).

As to why the Silver acetate is soluble, I refer the reader to "The Effect of Some Salts on the Solubility of Silver Acetate and of Silver Nitrate in Acetic Acid at 30°", by Ralph K. Birdwhistell, ...with the 1st page available at http://pubs.acs.org/doi/abs/10.1021/ja01609a016?journalCode=...

My take: the NaCl reacts with some of the created AgAc forming AgCl and sodium acetate, with the latter apparently extending the solubility of AgAc in acetic acid in dilute solutions per the article.

[Edited on 8-8-2016 by AJKOER]

PHILOU Zrealone - 8-8-2016 at 06:59

Quote: Originally posted by AJKOER

Try microwaving a mix of elemental silver (or Sterling silver which is Ag mixed with Cu) with 3% H2O2, 5% acetic acid (vinegar) and a very small amount of sea salt (which acts initially as an electrolyte for this electrochemical based dissolution reaction) to form a dilute solution of soluble silver acetate (and some copper salts with Sterling silver).

As to why the Silver acetate is soluble, I refer the reader to "The Effect of Some Salts on the Solubility of Silver Acetate and of Silver Nitrate in Acetic Acid at 30°", by Ralph K. Birdwhistell, ...with the 1st page available at http://pubs.acs.org/doi/abs/10.1021/ja01609a016?journalCode=...

My take: the NaCl reacts with some of the created AgAc forming AgCl and sodium acetate, with the latter apparently extending the solubility of AgAc in acetic acid in dilute solutions per the article.

[Edited on 8-8-2016 by AJKOER]

And what happens with the cementation reaction?
2 Ag⁽⁺⁾+ Cu_(s) --> 2 Ag_(s) + Cu⁽²⁺⁾
Cu metal is more electropositive than Ag and thus displace it from its salts...

AJKOER - 8-8-2016 at 20:38

Sterling silver is an alloy of silver containing 92.5% by weight silver and 7.5% other metals, usually copper.

I suspect the Cu dissolves faster in vinegar/H2O2 than does the Ag, so the reaction:

2 Ag(+) + Cu(s) --> 2 Ag(s) + Cu(2+)

over emphasizes the likely presence of freshly created silver. But, if formed, it quickly reacts with the excess vinegar/H2O2. That is, one does not leave a large piece of Sterling silver in a solution devoid of acetic acid/H2O2. The final products are acetates of both metals.

Separation of respective Ag/Cu salts a bit off topic, but one could start by adding a sheet of copper metal.

[Edited on 9-8-2016 by AJKOER]

NEMO-Chemistry - 10-8-2016 at 01:54

I have managed to find a cheap source of silver! As most of you dont live near me i dont mind sharing

.

I went looking around charity shops (shrift shops in the states i think), and alot of the lower end ones sell old cutlery. If you delve through the trays you can often find silverware very cheaply!

I managed to find 24 various items like knives and forks for around 5p each!! Some are plated but some simply say sterling silver with a hallmark on. I have no idea how much silver is in them but it must be worth it for the price!

It at least should give me a reasonable amount of silver nitrate once i have recovered the silver.

alive&kickin - 10-8-2016 at 05:51

NEMO, sterling silver is a jewelry standard of 92% silver with 8% copper. You've got a bit of silver there.

clearly_not_atara - 19-1-2017 at 17:39

I posted a thread about silver lactate earlier, which has roughly seven times the solubility of silver acetate (without help). Silver sulfamate has also come up as having similar solubility. I believe that silver can be dissolved in either acid with the help of a little H2O2. However, there were some concerns about the stability of silver lactate, although I have yet to find a reference suggesting that it autooxidizes, and the hydroxyl group is more electron-deficient than a typical alcohol because of the electron-withdrawing effect of the carboxyl group, so it might not.

However, there's still room to improve on this, since neither salt is as soluble as silver fluoride or silver nitrate, which are both very soluble but involve using dangerous HF or HNO3. Tetrafluoroborate, hexafluorophosphate, and triflate are also highly soluble, but very hard to obtain, of course.

http://en.wikipedia.org/wiki/Oxamic_acid

^but this might not be. Silver oxamate may have an even higher solubility than the lactate, since oxamic acid can form more hydrogen bonds than lactate. Oxamic acid is as easy to synthesize as just heating monoammonium oxalate And of course the amide group is much less oxidizable.

EDIT:

https://books.google.com/books?id=xR86AQAAIAAJ&pg=PA56&a...

Paper title: "Decomposition of Bioxolate of Ammonia by Heat" -- I think you know where this is going

Quote:

A solution of oxamate of ammonia and oxamate of baryte, treated with nitrate of silver, furnished an abundant gelatinous mass, demi-transparent, and which soon becomes opaque. This precipitate is completely dissolved in the liquor when we raise the temperature,

(bold mine) It actually may be quite soluble, although not as soluble as the ammonium salt or AgNO3

[Edited on 20-1-2017 by clearly_not_atara]

[Edited on 20-1-2017 by clearly_not_atara]

DraconicAcid - 19-1-2017 at 20:53

I wonder how soluble silver glycinate is....

PHILOU Zrealone - 20-1-2017 at 04:46

Quote: Originally posted by DraconicAcid

I wonder how soluble silver glycinate is....

Glycolate?
Tartrate?
Formate?

clearly_not_atara - 23-1-2017 at 12:41

http://pubs.rsc.org/-/content/articlelanding/1904/ct/ct90485...

Paper states that silver oxide and alkyl iodides can be used together to esterify oxamic acids, with the example used being oxanilic acid (N-phenyloxamic acid). It seems likely that this involves a silver salt intermediate, since alkyl iodides would normally react with Ag2O to give ethers or alcohols, IIRC.

pesco - 9-7-2025 at 23:02

Quote: Originally posted by bfesser

Amos Backstrom, I understood what you meant. I disagree. For preparing AgNO₃, 50-60% HNO₃(aq) should be just fine. If it's too concentrated, the silver will dissolve slowly, if appreciably (passivation, limited solubility, etc.). Preparation of nitric acid and it's use in preparing silver nitrate is one of those topics which has been discussed ad nauseam. I suggest you try searching the fora and reading through what's already been written on the subject before asking more questions. I think you'll find that all of your questions have already been answered.

Silver Nitrate Synthesis

[Edited on 25.11.13 by bfesser]

Concentrated:
3 Ag + 4 HNO₃ --> 3 AgNO₃ + 4 NO + 2 H₂O
Diluted:
Ag + 2 HNO₃ --> AgNO₃ + 2 NO₂ + 2 H₂O

From above you can see that concentrated HNO₃ is less efficient than diluted in terms of HNO₃ use per given mass of Ag.
The borderline lies around 4.5M.
From experience I know that dilute takes longer to dissolve silver, but not much longer and taking into account savings on HNO₃ its well worth it. Excess water can be evaporated after dissolution if needed.

chloric1 - 10-7-2025 at 16:25

Quote: Originally posted by woelen

If you have access to nitrates and sulphuric acid, then why not distill some to make HNO3 yourself? You should not make fuming HNO3, making a 60% solution should do the trick. Just add water and KNO3 to H2SO4 and boil off the liquid at 120 C or so.

I have access to purchase nitric acid but why pay $100 per quart when it literally costs me $4.75 to make 150-200 ml of 72-73% nitric acid. I just have to dedicate time to making it.
BTW…I have heard of silver etching with ferric nitrate but never tried it and don’t know how good it is. Seems reasonable that ferrous nitrate and silver nitrate would be produced
[Edited on 7/11/2025 by chloric1]

[Edited on 7/11/2025 by chloric1]

Metallophile - 10-7-2025 at 18:42

Quote: Originally posted by pesco

Maybe I'm missing something, but those reactions don't seem to balance, and also seem to contradict your point. I'm not doubting your assertion, but I am confused.