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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: AdiDex on February 16, 2018, 10:46:51 AM

Title: Self reduction of least electropositive metals
Post by: AdiDex on February 16, 2018, 10:46:51 AM

In most of the place, it is given that less electropositive metal sulfides can be self-reduced eg. Cu, Pb, Hg etc. But I didn't find out any reason why least electropositive metals like Ag and Au can't be self-reduced?
Why Ag₂S or Au₂S can't be self-reduced?

I am not able to find out any single source which suggests that Au or Ag can be extracted via auto reduction method. Even the Reduction potential of Ag⁺ is +0.7996 V and Reduction potential of Cu²⁺ is +0.337 V.

P.S. I found out only this paper, otherwise, there is no mention in the literature.
https://link.springer.com/article/10.1007/s10973-012-2300-z (https://link.springer.com/article/10.1007/s10973-012-2300-z)

Title: Re: Self reduction of least electropositive metals
Post by: chenbeier on February 16, 2018, 11:33:02 AM

These sulfide are almost insoluble, so there is no way to get free ions which can be reduced. You can burn (roast) it to get the oxide and dissolved in acid.