Geometrical shapes of the complexes fromed by the reaction of ` Ni^(2+)` with ` CO,CN^-` and `H_2O`, respecitively , are :

Options

A. Octahedral , tetrahedral and square planar
B. Tetrahedral , square planar and octahedral
C. square planar , tetrahedral and octahedral
D. Octahedral , square planar and octahedral

Answer

B

Explanation

`Ni ^(2+) + 4CN^(-) to [Ni(CN)_(4)]^(2-)`
here .`Ni ^(2+) ` has ` d^(6) ` configuration with `CN^(-) ` as strong ligands

`d^(8) ` -configuration is strong field ligand gives `dsp^(2) ` hybridisation , hence square planar geometry .
`NI^(2+)+4Cl^(-) to [NiCl_(4)]^(2-)`
here ,`Ni^(2+) ` has `d^(8)` - configuration with `Cl^(-)` as weak ligand

`d^(8) ` - configuration in weak field ligand gives
`sp^(3)-` hybridisation , hence tetrahedral geometry .
`Ni^(2+)` with ` H_(2)O` forms `[Ni(H_(2)O)_(6)]^(2+)` complex and `H_(2)O` is a weak ligand .

Therefore ` ,[Ni (H_(2)O)_(6)]^(2+)` has octahedral geometry .