Chemical Forums

Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: ade93 on May 06, 2011, 04:09:59 PM

Title: How do I get the silver from Na3[Ag(S2O3)2]?
Post by: ade93 on May 06, 2011, 04:09:59 PM
Hi
  I would be very happy if someone could give me a method to get the silver from Na3[Ag(S2O3)2], I got it first by dissolving silver chloride with sodium thiosulphate (AgCl(s) + 2S2O32−(aq) → [Ag(S2O3)2]3−(aq) + Cl−(aq) )
 
  Also, is there any way to obtain the silver chloride by reversing the reaction? Should it be in a freezer?

 Have good day! 
  / Adam, 17
Title: Re: How do I get the silver from Na3[Ag(S2O3)2]?
Post by: ampakine on May 07, 2011, 06:14:48 PM
Thiosulphate is a pretty weak field ligand, its well below H2O on the spectrochemical series. I'm taking a wild guess here but I'd say add concentrated ammonia solution to replace the thiosulphate ligand with NH3. Reacting with HCl then should cause the NH3 ligand to be replaced with H2O and adding excess HCl should cause AgCl to precipitate out. Like I said that was all a wild guess, I have no idea if any or all of that will work but theres only 1 way to find out.

EDIT: Ah wait that makes no sense. You'd just be stuck with the [Ag(H2O)2] ion.
Title: Re: How do I get the silver from Na3[Ag(S2O3)2]?
Post by: Athiril on May 08, 2011, 12:55:27 AM
If you wanted elemental silver. You can take the silver halide and reduce it with ascorbic acid + sodium hydroxide. pH 11-12. Paracetamol + sodium hydroxide + sodium sulphite, hydroquinone + sodium hydroxide + sodium sulphite would all work too.
Title: Re: How do I get the silver from Na3[Ag(S2O3)2]?
Post by: Borek on May 08, 2011, 05:29:12 AM
This is a known problem, google for silver recovery/reclaiming from spent/waste fixing bath/solution.
Title: Re: How do I get the silver from Na3[Ag(S2O3)2]?
Post by: Athiril on May 08, 2011, 06:33:28 AM
A new device came out last year for that for the home user.

http://www.apug.org/forums/forum146/68135-silver-magnet-silver-recovery-device.html