elementcollector1
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Platinum anode - odd reaction
My 1" Pt wire is doing something very strange. I taped it to a copper wire to act as anode, but every time I turn it on it creates several
blackish-brown insoluble particles. This has happened in chloride solutions mainly, but I have not had the chance to test it with other anions.
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hissingnoise
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It's most likely that the particles are chips of copper oxide!
Taping the wires together won't form a secure connection and some surface oxidation will occur . . .
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elementcollector1
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How resistant is platinum wire to chlorine, anyway? It should be immune, but still.
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hissingnoise
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Platinum is practically inert to chlorine . . .
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Fleaker
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Not so at all.
Bulk platinum might be (sheets, thick wire and the like), but I use Cl2/HCl to solvate platinum sponge every day.
Neither flask nor beaker.
"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
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elementcollector1
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Well, sponge is probably a bit more reactive than wire.
Still, this worries me, as I thought platinum was the ultimate anode; inert to just about anything but aqua regia...
I don't need it for anything but a chlorine-related anode, though. And an element sample. What does tarnished platinum look like?
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kadriver
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I use chlorine (HCl/clorox) to dissolve platinum from catalytic converter substrate. Chlorine will dissolve platinum, but only very slowly.
kadriver
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kadriver
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Quote: Originally posted by elementcollector1  | Well, sponge is probably a bit more reactive than wire.
Still, this worries me, as I thought platinum was the ultimate anode; inert to just about anything but aqua regia...
I don't need it for anything but a chlorine-related anode, though. And an element sample. What does tarnished platinum look like?
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I was making some standard test solution by dissolving 100mg of pure platinum metal in hot aqua regia. The piece of platinum was about the size of a
grain of rice.
It took me almost eight hours with multiple additions of fresh aqua regia and constant heat to get it to dissolve - even after all that there was
still a tiny thread of the metal that remained undissolved.
Also, platinum will not discolor after being heated to redness or even bright yellow. It is one of the few metals that has this quality.
If one wants to prove a piece of platinum all you need to do is heat it until it glows bright yellow, then let it cool to room temp. If it is
platinum, then it will look as if the a flame had never touched it.
kadriver
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