# Ammonia does not dissolve AgCl at once



## arthur kierski (May 28, 2010)

I have to use up to 3 separated times to dissolve AgCl with NH4OH----i do this because i have to leave behind PbCl2 (which does not dissolve in NH4OH)
eliminating Pb with hot water is very tiring---------any suggestions?







Formula edited by Lou for everyone's clarity. Arthur, please next time use the correct formulas, I know you know better.


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## lazersteve (May 28, 2010)

Arthur,

The powder will need to be stirred continuously. The key is to expose as much of the chloride as possible to the solvent.

Steve


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## machiavelli976 (May 28, 2010)

a more concentrated NH4OH will work faster


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## lazersteve (May 28, 2010)

machiavelli976 said:


> a more concentrated NH4OH will work faster





Wiki said:


> Diamminesilver(I), [Ag(NH3)2]+, the active species in Tollens' reagent. Formation of this complex can also help to distinguish between precipitates of the different silver halides: *silver chloride (AgCl) is soluble in dilute (2M) ammonia solution,* silver bromide (AgBr) is only soluble in concentrated ammonia solution while silver iodide (AgI) is insoluble in aqueous solution of ammonia.



2M aqua ammonia is about 1.15% ammonia by weight.

Steve


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## shyknee (May 28, 2010)

arthur maybe what is over looked is eliminating the Pb some where during your processes.


let us all know what is the feed material you have and what process your using to arrive at silver and lead chlorides mixed


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## arthur kierski (May 28, 2010)

Shyknee,the feed material is iron clips with silver tips(it comes from motor cars relays)---these clips are dissolved in hno3 ---- nacl(table salt ) is added to the solution and agcl is formed with lead chloride-when one adds nh4oh, agcl is dissolved and lead remains as a powder---as i said nh4oh did not dissolve agcl imediatelly(just partly)


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## shyknee (May 28, 2010)

arthur kierski said:


> Shyknee,the feed material is iron clips with silver tips(it comes from motor cars relays)---these clips are dissolved in hno3 ---- nacl(table salt ) is added to the solution and agcl is formed with lead chloride-when one adds nh4oh, agcl is dissolved and lead remains as a powder---as i said nh4oh did not dissolve agcl imediatelly(just partly)


 Steve (or anyone) a question if I may? After Arthur dissolved the clips if he added a little sulfuric would that drop the Pb as a sulfate that he could filter out before adding the salt ? is it safe to do or will it not work ?


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## lazersteve (May 28, 2010)

shyknee said:


> ... After Arthur dissolved the clips if he added a little sulfuric would that drop the Pb as a sulfate that he could filter out before adding the salt ? is it safe to do or will it not work ?



Silver sulfate is not soluble in water (only slightly so) and therefore most of it would be precipitated with the lead sulfate.

Steve


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## shyknee (May 28, 2010)

thanks Steve. I thought the silver would stay as silver nitrate by adding just a little sulfuric thanks for the correction  and sorry arthur


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## arthur kierski (May 29, 2010)

Steve, in an ar solution with gold,i add some sulfuric acid before smb is added and if lead is present a white precipitate comes down---i filter the solution to eliminate this pbso4 and then add smb-----could this as shyknee asked not be done with a silver nitrate with some lead nitrate solution even if some silversulfate would precipitate with the lead sulphate? i ask this because the silver sulfate could be separated from the lead sulfate with ammonea---------


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## butcher (May 29, 2010)

this is only speculation on my part--- 

if we have silver nitrate, with some lead nitrate, and added a small amount of sulfuric acid, we would be making some nitric acid, and lead sulfate, and silver sulfate , now which will be more soluble in the nitric acid solution? lead being higher in series, may not precipitate lead sulfate before the silver silver sulfate? 

sorry I don't have the answer, but without further study I would not add the sulfuric to silver nitrate solution to try and remove lead.


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## shyknee (May 29, 2010)

shyknee said:


> thanks Steve. I thought the silver would stay as silver nitrate by adding just a little sulfuric thanks for the correction  and sorry arthur


the key word "small" amount of sulfuric the intent is not to drop everything as a sulfate.
would most of the lead or all of it drop( with good mixing )before some of the silver drops out as a sulfate ?


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## butcher (May 29, 2010)

2AgNO3 + PbSO4 --> Ag2SO4 + Pb(NO3)2

silver nitrate and lead sulfate yields silver sulfate and lead nitrate.

lead is higher in series so it is soluble in the nitrate and silver lower in series is insoluble silver sulfate.

if you added enough sulfuric acid you may be able to precipitate all the silver as a sulfate, and if you were real good at guessing how much, may keep your lead as nitrate in the sulfuric solution. :twisted: 

this is just not the way to go forget trying to get the lead out of silver nitrate with sulfuric.


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## qst42know (May 29, 2010)

arthur kierski said:


> Shyknee,the feed material is iron clips with silver tips(it comes from motor cars relays)---these clips are dissolved in hno3 ---- nacl(table salt ) is added to the solution and agcl is formed with lead chloride-when one adds nh4oh, agcl is dissolved and lead remains as a powder---as i said nh4oh did not dissolve agcl imediatelly(just partly)



Skip the salt and cement the silver with copper. Leave the lead nitrate in solution.


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## butcher (May 30, 2010)

wow too simple, and it is so much easier to melt the silver.

you make it too easy :lol:


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## shyknee (May 30, 2010)

there it is !!!! 8) had my blinders on i could only see salts not the copper!!! :lol:


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## qst42know (May 30, 2010)

Though it doesn't answer the original question it reminds me of an old joke.

A man goes to the Doctor and says "Doc it really hurts when I do this." The Doctor looks the man in the eye and says "Stop doing that!" :mrgreen:


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## butcher (May 30, 2010)

silver sulfate is only Slightly sparingly soluble 1.2 g/100ml h20.
lead sulfide is insoluble 4.25 mg/ 100ml h20.

as long as lead does not replace the silver in the reaction.
there may be a small window here to sqeeze through?
guess you will have to try some controlled expieriment to see.


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## g_axelsson (Jun 1, 2010)

butcher said:


> silver sulfate is only Slightly sparingly soluble 1.2 g/100ml h20.
> lead sulfide is insoluble 4.25 mg/ 100ml h20.



I think you mean lead sulfate, lead sulfide is even more insoluble in water (2.6 x 10^-6 mg/ 100ml H2O ).

/Göran


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## butcher (Jun 3, 2010)

thanks for your sharp eye, yes lead sulfate, sorry had IDE on the brain.


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