Discuss the relative stability in aqueous solution of +2 oxidation states among the elements: Cr, Mn, Fe and Co

Explanation

The relative stability of the +2 oxidation states ( decreasing order ) can be compared in terms of `E^(@)` values. `(M^(2+)//M)`
`Mn^(2+)(-1.18V) gt Cr^(2+)(-0.90 V) gt Fe^(2+)(-0.44 V) gt CO^(2+)(-0.28 V)`