Which of the following statements is correct?

Options

A. Potassium ferrocyanide is diamagnetic where as potassium ferricyanide is paramagnetic.
B. Crystal field splititing in ferrocyanide ion is greater than that of ferricyanide ion.
C. The geometry of `Ni(CO)_(4)` and `[NiCl_(2)(PPh_(3))_(2)]` are tetrachedral.
D. (A) & (D)

Explanation

(A) `Fe^(2+)`

`d^(2) sp^(3)` hybridisation
All ecectrons are paired, so diamangentic. & `Fe^(3+)`

`d^(2) sp^(3)` hydridisation
It contains one unpaired electron, so paramagnetic. (B) Ggreater the charge (i.e., oxidation state) on central atom greater will be the splitting. Hence `[Fe^(III)(CN)_(6)]^(3-)` has greater splitting than `[Fe^(III)(CN)_(6)]^(4-)`
( C) Ni will be in `sp^(3)` hybridisation state in both `Ni(CO)_(4)& [NiCl_(2)(PPh_(3))_(2)].`
`Ci(CO)_(4):`
`sp^(3)` hybridisation
(tetrahedral)
`[NiCl_(2)(PPh_(3))_(2)],PPh_(3)` is strong fild ligand but being buliker group gavorus tetrahedral geometry.