Question

Amongst `Ni(CO)_(4),[Ni(CN)_(4)]^(2-)` and `[NiCl_(4)]^(2-)`
A. `Ni(CO)_(4) and |NiCl_(4)|^(2-)` are diamagnetic and `|Ni(CN)_(4)|^(2-)` is paramagnetic
B. `Ni(CN)_(4) and |NiCl_(4)|^(2-)` are diamagnetic and `Ni(CN)_(4)` is paramagnetic
C. `Ni(CO)_(4) and |Ni(CN)_(4)|^(2-)` are diamagnetic and `|NiCl_(4)|^(2-)` paramagnetic
D. `|NiCl_(4)|^(2-) and |Ni(CN)_(4)^(2-)` are diamagnetic and `Ni(CO)_(4)` is paramagnetic.

Answer 1

The electronic configuration of `|Ni(CN)_(4)|^(2-) |NiCl_(4)|^(2-)` and ` Ni(CO)_(4)` are following `Ni^(2+)` in `|Ni(CN)_(4)|^(2-)`

CO and `CN^(-)` are strong ligands so they produce pairing of electrons so these complexes are diamagnetic while `Cl^(-)` is a weak ligand so it does not undue passing of electrons so its comple is paramagentic.