ldanielrosa
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mystery metal, resists nitric acid
Some time ago, I dissolved a Chinese silver spoon in nitric acid to verify the silver content. It came up about 70%, which I suspected from the
markings on the stem.
I used copper wire to displace the silver, dried and weighed the precipitate. Then I dissolved the reclaimed silver in nitric acid again so that I'd
have a supply of the nitrate salt. The solution was colorless (no copper), but some small portion wouldn't dissolve.
I set this aside, washed and dried it, then tried again. No reaction. Any ideas for an element that would behave this way?
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xfusion44
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Maybe stainless steel or titanium - less likely.
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Oscilllator
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Since the material dissolved in nitric acid once, but then didn't dissolve the second time it it possible that the unknown material is some kind of
contamination? I don't see any reason why something could be dissolved once but not twice.
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blogfast25
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SS (Fe + Cr, mainly) dissolves in nitric in a jiffy. Ti forms insoluble TiO2 with nitric.
+++++++++++
Silver objects often contain small amounts of even 'nobler' elements due to repeated recycling and thus mixing with other silver alloys coming from
jewellery, cutlery, ornaments etc. Commercial silver objects may thus contain Au, Pt and other 'nobles' that aren't soluble in nitric acid.
[Edited on 24-8-2015 by blogfast25]
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fusso
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Quote: Originally posted by ldanielrosa  | Some time ago, I dissolved a Chinese silver spoon in nitric acid to verify the silver content. It came up about 70%, which I suspected from the
markings on the stem.
I used copper wire to displace the silver, dried and weighed the precipitate. Then I dissolved the reclaimed silver in nitric acid again so that I'd
have a supply of the nitrate salt. The solution was colorless (no copper), but some small portion wouldn't dissolve.
I set this aside, washed and dried it, then tried again. No reaction. Any ideas for an element that would behave this way? |
Did u filter the soln before adding Cu? if not then the ppt is probably from the contaminated Ag powder.
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Bert
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Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
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Did you notice the thread is 3 years old and the author has not signed in for 2 years?
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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