silvergrahm
Harmless
Posts: 36
Registered: 19-10-2012
Member Is Offline
Mood: No Mood
|
|
Quick silver sulfide
So, we all know the old trick for removing silver sulfide tarnish from old silverware: fill a sink with hot water, add baking soda, and place foil of
aluminum over the silver ware.
But how would you do this in reverse? I guess fuming silver with hydrogen sulfide would do the trick, if you want to die. But is there an aqueous
solution of some sulfide that does not hydrolize into hydrogen sulfide?
I'd also love a detailed explanation of what is going on to remove the silver sulfide w/ aluminum and baking soda. The bicarbonate is an electrolyte?
|
|
|
DutchChemistryBox
Hazard to Self
Posts: 74
Registered: 24-3-2013
Location: Strasbourg
Member Is Offline
Mood: No Mood
|
|
Maybe you could make a solution of K2S or Na2S.
And then electrolyse it with the silver in the solution.
Na2S(s) > 2Na+(aq) + S2-(aq)
2Ag(s) > 2Ag+(aq) + 2e
2H2O(l) + 2E > H2(g) + 2 OH–(aq)
----------------------------------------
2Ag(s) + 2H2O(l) >2Ag+(aq) + H2(g) + 2 OH–(aq)
Then you'll have a solution with Ag+,S2-,Na+,OH–
The Ag+ and the S2- aren't soluble in water together:
2Ag+(aq) + S2-(aq) > Ag2S(s)
Then you can filter it and you'll have your silversulfide.
At least, that is what i'm thinking
[Edited on 7-4-2013 by DutchChemistryBox]
|
|
|
Metacelsus
International Hazard
Posts: 2532
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
First, S2- (pKa > 14) doesn't exist in aqueous solution, even at pH 15. The active ion would be HS-.
Na2S(s) + H2O(l) -> 2 Na+(aq) + OH-(aq) + HS-(aq)
Second, the Ag+ reacts both with HS- AND OH-. Four reactions are possible (I think).
2 Ag+(aq) + 2 OH-(aq) -> Ag2O(s) + H2O(l)
2 Ag+(aq) + OH-(aq) + HS-(aq) -> Ag2S(s) + H2O(l)
2 Ag+(aq) + OH-(aq) + HS-(aq) ->Ag2O(s) + H2S(g)
2 Ag+(aq) + 2 HS-(aq) -> Ag2S(s) + H2S(g)
I'm not sure which one(s) take place. For better results, try sodium hydrosulfide (NaHS) instead of sodium sulfide.
Finally, silver suldife is Ag2S, not Ag2Cl. 
[Edited on 6-4-2013 by Cheddite Cheese]
|
|
|
silvergrahm
Harmless
Posts: 36
Registered: 19-10-2012
Member Is Offline
Mood: No Mood
|
|
Aqueous HS. Is that hydrosulfuric acid? Trying to keep the HS down. Even under the hood I'm scared.
Are their sulfurous compounds that will produce a sulfide with Ag, but not with other metals, namely copper? Zinc? Iron?
|
|
|
elementcollector1
International Hazard
Posts: 2684
Registered: 28-12-2011
Location: The Known Universe
Member Is Offline
Mood: Molten
|
|
H2S is the compound you're looking for, and it's not a problem under a hood.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
|
|
|
DutchChemistryBox
Hazard to Self
Posts: 74
Registered: 24-3-2013
Location: Strasbourg
Member Is Offline
Mood: No Mood
|
|
@Cheddite Cheese:
I didn't thought about the fact that S2- is such a strong base.
@Silvergrahm
Are you going to try it with NaHS? I'm curious about the results.
|
|
|
silvergrahm
Harmless
Posts: 36
Registered: 19-10-2012
Member Is Offline
Mood: No Mood
|
|
I think I might whip up something that yields H2S on hydrolysis, after all. I'm doing this on silver plated copper, really no need to submerge it I
guess, can just add MgS or something of that nature and fume the plate over the gas that wafts off.
Is MgS the best choice? Maybe not...
[Edited on 8-4-2013 by silvergrahm]
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
Tarnishing silver is very simple, since it happens so readily. Just place your silver object in a ziploc bag along with a rotten egg, or some sulfur
powder. You might want to do this outside anyway, as I've found that the sulfur smell seeps through the bag, no matter how many bags you use!
From the abstract of an article I can't access the full text for:
"Contact with materials that contain sulfur compounds, such as hardboiled eggs, mayonnaise, mustard, and rubber bands can cause tarnish. In air, a
silver object can tarnish owing to the reaction of silver with hydrogen sulfide (H2S). This is a gas found in the air as a result of some industrial
processes and the decomposition of dead plants and animals."
|
|
|
chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
Member Is Offline
Mood: LaGrangian
|
|
I want to tarnish some silver jewelry to get a nice patina. I did this in the past using a cutting oil with S in it. In this, these cases, there are
silver "ropes" and other crevice types involved so cleanup is an issue. I'm thinking of burning some S in the hod and holding the objects in the smoke
(vapor).
[Edited on 22-4-2016 by chemrox]
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
|
|
|
Metacelsus
International Hazard
Posts: 2532
Registered: 26-12-2012
Location: Boston, MA
Member Is Offline
Mood: Double, double, toil and trouble
|
|
I would think that SO2 wouldn't tarnish silver like H2S would. However, there might be enough unburned S in the smoke to cause
the silver to tarnish.
Instead of burning the S, you could try heating it in a closed container along with the silver item. It should sublime onto the silver and cause it to
tarnish.
|
|
|
JJay
International Hazard
Posts: 3440
Registered: 15-10-2015
Member Is Offline
|
|
I would think the heating silver powder with flowers of sulfur in a crucible would do the trick.
|
|
|
violet sin
International Hazard
Posts: 1475
Registered: 2-9-2012
Location: Daydreaming of uraninite...
Member Is Offline
Mood: Good
|
|
Liver of sulfur anyone? Made specifically to blacken/age/patina jewelery. Like the black shadows in the crevices of a class ring. It is submerged
to color the piece, then buffed on the surface highspots, leaving the dark inbetween the nooks
Wiki page
https://en.m.wikipedia.org/wiki/Liver_of_sulfur
Being used
https://m.youtube.com/watch?v=gCiKs60kXJ4
Being made
https://m.youtube.com/watch?v=30hEhFJ8Ejc
|
|
|
unionised
International Hazard
Posts: 5105
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
Some sort of polysulphide seems like a god choice.
|
|
|
BromicAcid
International Hazard
Posts: 3227
Registered: 13-7-2003
Location: Wisconsin
Member Is Offline
Mood: Rock n' Roll
|
|
Liver of sulfur is incredibly easy to make, I have used it several times for art projects. A few pellets of NaOH, some water, and a few pinches of
sulfur, not much to it. Attached is a photo of the marquee of my arcade cabinet, I electroplated the dark parts on the brass plate with copper and
then treated with 'liver of sulfur' to achieve the dark appearance.
Edit: Am I the only one that read this and registered quicksilver sulfide? I.e., mercury sulfide?
[Edited on 4/23/2016 by BromicAcid]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
