Question

The ion `Cr^(2+)` is redusing agent while that of `Mn^(3+)` is an oxidising agent though both have `3d^(4)` configuration.
This is because
A. `Cr^(2+)` configuration results from `d^(3) to d^(4)` while that of `Mn^(3+)` result from highly stable `d^(5)` configuration
B. `Cr^(2+)` Configuration results from `d^(4) to d^(3)` while that of `Mn^(3+)` results from highly stable `d^(5)` configuration.
C. Both the ions, `Cr^(2+)` and `Mn^(3+)` results from `d^(5)` configuration.
D. `Cr^(2+)` configuration results from `d^(5)` while that of Mn results from `d^(5)`

Answer 1

Correct Answer - B
`Cr^(2)` is reduceing in nature because its electronic configuration changes from `d^(3)` the latter having a half filled `t_(2g)` level whereas `Mn^(3+)` resultes fromm `d^(5)` configurationwhich is highly stable. Therefore, `Mn^(3+)` is oxidising in nature.