How would you account for the increasing oxidising power in the Example series `VO_(2)^(+) lt Cr_(2)O_(7)^(2–)lt MnO_(4) ^(-)`

Explanation

This is due to the increasing stabil,ity of the lower species to which they are reduced.
(i). `Mn^(VII)O_4^(ɵ)` is reduced to more stable configuration `Mn^(2+)(3d^5)` and `Mn^(4+)(3d^3` or `t_(2g)^3)`.
Hence, it acts as strongest oxidising agent amongst the given ions.
(ii). `Cr_2^(VII)O_7^(2-)` is reduced to a stable configuration `Cr^(3+)(3d^3` or `t_(2g)^(3))`. Hence it acts as a stronger oxidising agent.
(iii). In `(V^VO_2)^(o+)` , V is in `+5` O.S having `3d^0` stable configuration and is therefore not reduced effectively. Thus, the increasing oxidising power is as follows:
`VO_2^(o+)ltCr_2O_7^(2-)ltMnO_4^(ɵ)`