question_answer

The complex showing a spin only magnetic moment of 2.82 BM is

A)  \[[Ni{{(CO)}_{4}}]\]                       

B)  \[{{[NIC{{l}_{4}}]}^{2-}}\]

C)  \[[Ni{{(PP{{H}_{3}})}_{4}}]\]                     

D)  \[{{[Ni{{(CN)}_{4}}]}^{2-}}\]

Correct Answer: B

Solution :

                In \[{{[NiC{{i}_{4}}]}^{2-}}\], Ni is in + 2 oxidation state. Since, OF is a weak field ligand, it does not cause pairing of electron. \[N{{i}^{2+}}=3\,{{d}^{8}}\]                 Number of unpaired electrons, \[n=2\] \[\mu =\sqrt{n(n+2)}=\sqrt{2(2+2)}\]                                 \[=\sqrt{8}\,BM=2.82\,BM\]