Ag and H2O2

[samuel-a]

Been trying to clean silver powder, so i figured (don't know whay...) i will dry it and wash it with H2O2 3%.
It reacted quiet vigorously, and form a cloudy solution that will not filter out.
And a distinct Yeast smell.

I decided to check if some silver is in solution and submerged copper piece.
Amazingly, two day later it had a bulb of fluffy silver crystals around the tip of the Cu piece.

can someone elaborate what is going on it that process ?


Today i did the same thing, only this time, insted of submerging Cu piece, i added HCL and got what appers to be AgCl precipitation...

Same Q. as above...

 

[machiavelli976]

What is the source of your silver powder? The cloudy solution must contain silver hydroxide , catalyzed by some impurities. I don't remember solid silver reacting so vigorously with dilute H2O2.

 

[Anonymous]

silver catalyzes the break down of H2O2 into water and oxygen, there is a rocket engine based on this that uses a silver screen and highly concentrated H2O2.
The silver is not supposed to react.

Jim

 

[samuel-a]

my silver was at least 99%, and maybe with, probably Al2SO4 from the AgCl convertion....

but before the H2O2 i washed really well with H2O...

 

[Chumbawamba]

Maybe it reacted thusly because it was in powder form, and thus ample surface area for a reaction to take place?

 

[machiavelli976]

Powder form is not enough. But if each silver grain was covered with Ag2SO4 , the peroxide could convert it into SO2 and silver hydroxide i guess. Washing the powder well with water , might not be sufficient since the silver sulfate has a relatively solubility in tap water (0.79% at 20'C).What do you mean by "distinct Yeast smell" ?

 

[samuel-a]

What do you mean by "distinct Yeast smell" ?

Exactly what it sound's like.

the reaction emmited a smell of yeast ...
no idea whay...

 

[Juan Manuel Arcos Frank]

Samuel:

You have formed a kind of oxidant environment,H2O2 and chlorine of tap water could form silver chloride(film or powder, it depends on what form your silver is).

Avoid cleaning silver with H2O2,there are many solutions for silver cleaning.If you can not find them then use a 5% solution of HCl.

Hope it helps

Kindest Regards

Manuel

 

[machiavelli976]

Could be true but doesn't explain the cementing. I still believe there must have been some unreacted silver chloride or even silver sulfate along with the silver powder. Strong peroxide should easily convert them to AgOH. Have no clue about 3% H2O2 behavior instead.

 

[samuel-a]

Could be true but doesn't explain the cementing. I still believe there must have been some unreacted silver chloride or even silver sulfate along with the silver powder. Strong peroxide should easily convert them to AgOH. Have no clue about 3% H2O2 behavior instead.

Thnks for your input on this

 

[Shecker]

Silver oxide (hydroxide) is reducible with hydrogen peroxide. The H202 reacts with the AgOH causing the hydroxide to become water and oxygen is released. But the silver so produced is very fine in terms of particle size and is still an alkaline in terms of pH. You get a fine gray mud that is soluble in any acid. This may have its good points.

This also works on gold hydroxide and produces a fine yellowish mud that is also soluble in any acid.

Randy in Gunnison

 

[Lou]

Not so!


They are not soluble in just any acid. If they are, that is because they were incompletely converted. Usually, most NM oxides/hydroxides are more soluble in acids than the reduced noble metals.