Question

How would you account for the increasing oxidising power in the series $V{O}_2^{+}<C{r}_2{O}_7^{2-}<Mn{O}_4^{-}$?

Answer 1

$\text{Increasing oxidising power}$

In the given ions, the oxidation states of $V,Cr$ and $Mn$ are $+5,+6$ and $+7$ respectively.


As the oxidation state increases, the ease with which the ions accept electrons increases. After reduction $V,Cr$ and $Mn$ form more stable species where $Mn$ is in $+2$ oxidation state, is relatively more stable $\left(d^5\right)$ than $C{r}^{2+}\left(d^3\right)$ and $V^{3+}\left(d^0\right)$.