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

Explanation

`Cr^(2+)` is a stronger reducing agent than ` Fe^(2+)`. This is quite evident from the `E^(@)` values,
`E^(@)Cr^(3+)//Cr^(2+)=-0.41 V` and `E^(@)Fe^(3+)//Fe^(2+)=0.77V`.
Reason : `d^(4) to d^(3)` occurs when `Cr^(2+)` changes to `Cr^(3+)` ion while `d^(6) to d^(5)` takes place when `Fe^(2+)` gets converted to `Fe^(3+)` ion.
` underset ((d^(4)))(Cr^(2+)) to underset((d^(3)))(Cr^(3+))+e^(-), underset((d^(6)))(Fe^(2+)) to underset((d^(5)))(Fe^(3+)) +e^(-)`
Now, `d^(4) to d^(3)` transition is easier as compared to ` d^(6) to d^(5)` transition because in the second case, an electron is removed from a paired orbital which is rather difficult. Therefore , ` Cr^(2+)` is a stronger reducing agent than `Fe^(2+)`.