Hydrogen

[Anonymous]

Can hydrogen gas be used to precip metals from solution? ie copper, silver, and gold?

thanks
Jim

 

[Irons]

Can hydrogen gas be used to precip metals from solution? ie copper, silver, and gold?

thanks
Jim

I think you can safely add Arsenic, Antimony and Bismuth to that list.

 

[ander]

surely arsenic could react to make arsenic hydride which is volatile and rather toxic. I'm not sure about antimony and bismuth, but antimony can create antimony hydride too. Of course I mean freshly prepared hydrogen.

 

[Anonymous]

Can hydrogen gas be used to precip metals from solution? ie copper, silver, and gold?

thanks
Jim

I think you can safely add Arsenic, Antimony and Bismuth to that list.

Irons,
So if I put some zinc in HCL and bubbled the gas through a solution with just for instance gold chloride, would the gold precipate, forming HCL when the hydrogen replaces it? This seems like it should work to me based on the electrochemical chart, an could not any unreacted hydrogen be cycled back though until it was used up?

thanks
jim

 

[Lou]

It does not work.

 

[Anonymous]

Hi Lou,
I figured it would be too easy that way. Can you explain why it does not work?

thanks
Jim

 

[ander]

I suppose its because hydrogen can exist in two forms. First one- commonly use in industry, easy for storage is in form of two atoms molecule. It has all the major properties you know- extreme flammability, low boiling point etc. But at standart conditions it rather inreactive- you can mix it with oxidizer and it won't react itself- it needs something to initiate- something that brings enough energy make it reactive, eg. heating, palladium sponge, light (with chlorine). Then there can occour chain reaction- one molecule of hydrogen breaks into two atoms of hydrogen creating free radicals- they are very reactive and react with other moecules which then become free radicals and product of reaction and so on. The other thing is that your chlorine is bonded to gold so it's much less reactive thus reaction can go even harder.
The second state of hydrogen is one atom molecule. Due its nature to form two atoms molecule (like most of gaseous elements) it's extremely reactive and after creation in reaction the atoms recombine to molecular form in split of the second. This hydrogen is called in statu nascendi- in latin means "at the moment of creation". It can be made by putting acid and metal like zinc directly into reaction mixture. But this is what you want to avoid.
That is what I think could be the explanation.