Mercury univalent state

Removal of more than two electrons from the metal atoms practically never occurs, and the +2 oxidation state thus prevails. Although the + 1 oxidation state of mercury (Kg ) is also important, evidence for the existence of univalent zinc or cadmium is not completely convincing. 

In a solution containing an ionized mercurous salt in equilibrium with mercury metal, the fraction of dissolved mercury in the +2 state is independent of the concentration of univalent mercury. Show that this indicates that the mercurous ion is Hg + and not Hg+. 

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