Which is a stronger reducing agent `Cr^(2+)`or `Fe^(2+)` and why ?

Answer

`Cr^(2+)` is stronger reducing agent than `Fe^(2+)` .
change from `d^(4)` to `d^(3)` occurs in case of `Cr^(2+)` to `Cr^(3+)` but from `d^(6)` to `d^(5)` occurs in case of `Fe^(2+)`to `Fe^(3+)` . In a medium (like water) `d^(3)` is more stable as compared to `d^(5)` according to CFSE(CFSE for octahedral spiliting in case of `d^(3)` is `-1.2Delta_(0)` while for `d^(5)` is 0).