Among the following complexes `(K - P) : K_(3) [Fe(CN)_(6)] - K , [Co(NH_(3))_(6)]Cl_(3)- L , Na_(3)[Co("oxalate")_(3)]-M , [Ni(H_(2)O)_(6)]Cl_2 - N, K_(2) [Pt(CN)_(4)]-O and [Zn(H_(2)O)_(6)] (NO_(3))_(2)-P,` the diamagnetic complexes are

Options

A. `K,L,M,N`
B. `K,M,O,P`
C. `L,M,O,P`
D. `L,M,N,O`

Answer

c

Explanation

`Kimpliesk_(3)[Fe(CN_(6))],Fe^(3+) =3d^(5)` (odd electrons)
It is paramagnetic
`L implies [Co(NH_(3))_(6)]CI_(3),Co^(3+)=3d^(6)`
`NH_(3)` a strong field ligand and hence back pairing It is diamagnetic
` M implies Na_(3)[Co(OX)_(3)],Co^(3+)=3d^(6)`
Note Oxalate generally behaves as a weak field ligand but which Co, it behaves as a strong field ligand like `NH_(3)` `H_(2)O` So there will be back bonding It is diamagnetic
`Nimplies[Ni(H_(2)O)_(6)]CI_(2),Ni^(2+) =3d^(8)`(2unpaired electrons)
It is paramagnetic
`Oimplies K_(3)[Pt(CN)_(4)],Pt^(2+) =d^(3)`
`CN^(Θ)` a strong field ligand back pairing
It is diamagnetic .