a) State the hybridisation & magnetic behaviour of `[Cr(CO)_(6)]`
b) What are the various factors affecting crystal field splitting energy?
c) Which of the two is more stable and why?
`K_(4)[Fe(CN)_(6)]` or `[K_(3)[Fe(CN)_(6)]`

Explanation

a) Hybridisation state of Cr in the complex is `d^(2)sp^(3)`. It is octahedral and is diamagnetic.
b) N/A
c)`K_(3)[Fe(CN)_(6)]` is more stable than `K_(4)[Fe(CN)_(6)]` because Fe is in `+3` oxidation state while in the othe complex, it is in `+2` oxidation state. Moreover, the size of `Fe^(3+)` ion is smaller than that of `Fe^(2+)` ion. As a result, the ligands are held more closely by the `Fe^(3+)` ion than by `Fe^(2+)` ion.