The correct combination is

The correct combination is
  1. NiCl42-- Square planar; Ni(CN)42-- paramagnetic
  2. Ni(CN)42-- tetrahedral; Ni(CO)42-- paramagnetic
  3. NiCl42-- paramagnetic; Ni(CO)4- tetrahedral
  4. NiCl42-- diamagnetic; Ni(CO)4- square-planar

Solution

[NiCl4]2  
Tetrahedral 
Paramagnetic 

[Ni(CO)4]
Tetrahedral 
Diamagnetic 

Weak field ligand (WFL)
Strong field ligand(SFL)

NiCl42- NiCO4
Paramagnetic (2 unpaired electrons) Sp3
Ni2+Ar 3d8, 4s0, 4p0
Cl- (WFL) (No pairing) NiOAr3d8, 4s2, 4p0
  CO is SFL Ar3d10, 4s0, 4p0 (tetrahedral)

Asked in: JEE Main 2018 (15 Apr)

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