Which of the following is the strongest oxidizing agent ?

Options

A. `VO_(2)^(+)`
B. `Cr_(2)O_(7)^(2-)`
C. `CoO_(4)^(2-)`
D. `FeO_(4)^(2-)`

Explanation

On accoumnt of the steady in the effiective nuclear charge along the series, the tendency to exhibit higher oxidation states decreases. For example, the stability of the `(+6)` state decreases as follows :
`Cr_(2)O_(7)^(2-) gt MnO_(4)^(2-) gt FeO_(4)^(2-) gt CoO_(4)^(2-)` or `CrO_(4)^(2-)`
Therefore, the oxidizing power increases as follows
`CoO_(4)^(2-) gt gt FeO_(4)^(2-) gt MnO_(4)^(2-) gt Cr_(2)O_(7)^(2-) gt VO_(2) +` or `CrO_(4)^(2)`
This also due to the increasing stability of the lower species to which they are reduced.