Question

What is self-reduction?

Answer 1

Self-reduction is the process in which cations of the least reactive metals like Cu, Hg etc. reduce themselves without any use of external reducing agent.

For example :-

Reduction of HgO to Hg :-

$$\begin{gathered} 2\mathrm{HgO}\left(\mathrm{s}\right)+\mathrm{HgS}\left(\mathrm{s}\right)\to 3\mathrm{Hg}\left(\mathrm{l}\right)+{\mathrm{SO}}_2\left(\mathrm{g}\right) \\ \mathrm{Mercury}\left(\mathrm{II}\right)\mathrm{oxide}\mathrm{Mercuric}\mathrm{sulfide}\mathrm{Sulfur}\mathrm{dioxide} \end{gathered}$$