FrozenSpool
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Disposing of Tollen's Reagent After Silver Mirror Reaction
I am planning on plating a flask with silver but want to ensure that I dispose of the reagent properly afterwards to prevent a Ag3N
explosion. I know that the addition of dilute acid is standard procedure in destroying the reagent and am planning on using some 1M HCl. Is there any
issue with this procedure?
Also how much Tollen's reagent is needed to silver a flask? I am wanting to silver a 500mL Erlenmeyer and don't want to make more than needed. I am
planning on following NileRed's procedure (150mL 0.1M AgNO3, 9mL conc. NH3, 2.4g NaOH, and 1g dextrose), but am unsure on how to
scale it for my flask. Afterwards, I'll empty the flask into a beaker, rinse it with water, then neutralize with a generous amount of 1M HCl. Does the
silvered flask need to be cleaned a certain way?
Has anyone done this before and have any insight on scaling and disposing of the used reagent properly?
[Edited on 13-12-2023 by FrozenSpool]
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j_sum1
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Thread Moved
13-12-2023 at 12:08 |
DraconicAcid
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I'd add enough reducing agent to precipitate all the silver as the metal, and recover it.
If you want to leave the flask silvered, rinse well with distilled water. If you want to de-silver it, nitric acid.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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FrozenSpool
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Quote: Originally posted by DraconicAcid  | I'd add enough reducing agent to precipitate all the silver as the metal, and recover it.
If you want to leave the flask silvered, rinse well with distilled water. If you want to de-silver it, nitric acid. |
It is such a small amount of silver I will be using that I am not too worried about it. I am more concerned about disposing of the reagent properly
and am unsure if nitric acid is required or any HCl or H2SO4 will work.
I believe that HCl could work by neutralizing the spent reagent and precipitating out the silver as AgCl. But I am unsure whether it will successfully
neutralize all the reagent and whether it will de-silver the flask (which I do not want).
[Edited on 14-12-2023 by FrozenSpool]
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Johanson
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Frozen, sounds just like the well known silver christmas ornament lab. A little HCl will drop out whatever silver is left, correct. Don't add the HCl
to your newly plated flask - rather, pour out the remnants and then add it to that in a separate container. You're only doing one flask? Take the
rinsewater outside and flick it in the neighbor's yard. It's just dextrose, ammonia, and a small amount of caustic, and at that point perhaps a very
minute amount of Ag. I'm just kidding about the neighbor's yard. Amount for a flask? Probably enough to fill it around 1/3 full while swishing it
around. Rinsing? Go easy with the rinsing. If you start squirting DI water inside your newly plated flask you will peel off the micro-thin layer of
silver. Go very easy with any rinsing, that's all.
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Tsjerk
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The cleaner the glass to begin with, the better the attachment of the silver. You could for example clean with hot NaOH solution, a couple percent.
That will probably suffice.
[Edited on 17-12-2023 by Tsjerk]
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