the compound showing spin only mag moment 2.82 is

a) [Ni(CO)4] b) [Ni(Cl)4]2- c ) [Ni(CN)4]2-

THE ANSWER IS B BUT IAM VERY SURE THAT ITS C.....PLEASE HELP

Hi Vikas

The correct answer is B Ni²⁺ ion has 8 e^-  in 3d orbitals. so only 2 unpaired electrons are there. CN^- IS STRONG LIGAND SO IT will PAIR UP THE 2 e^-  AND FORM DSP²  hybridisation while Cl^- is weak field ligand so it will not suppport pairing and form sp³ hybridisation. Thus in b option 2 unpaired electrons are still present leading to magnetic moment 2.82.

Hope that helps.