For `M^(2+)|M` and `M^(3+)|M^(2+)` systems the `E^(0)` values for some metals are as follows :
`{:(Cr^(2+)"|"Cr,,-0.9V,,Cr^(3+)|Cr^(2+),,-0.4V),(Mn^(2+)"|"Mn,,-1.2V,,Mn^(3+)|Mn^(2+),,+1.5V),(Fe^(2+)"|"Fe,,-0.4V,,Fe^(3+)|Fe^(2+),,+0.8V):}`
Use this data to comment upon :
the ease with which iron can be oxidised as compared to a similar process for either chromium or manganese metal.

Explanation

Lower the reduction potential of a metal, greater is the ease with which it undergoes oxidation. Thus from the given values it can be predicted that Mn is most readily oxidised to `Mn^(2+)` and Fe is oxidised least readily to `Fe^(2+)`. Thus the tendency of the metals to undergo oxidation is : `Mn gt Cr gt Fe`.