question_answer

The diamagnetic species is/are

A)  \[{{[NiC{{l}_{4}}]}^{2-}}\]                            

B)  \[{{[Ni\,{{(CN)}_{4}}]}^{2-}}\]

C)  \[{{[CoC{{l}_{4}}]}^{2-}}\]                           

D)  \[{{[Co{{F}_{6}}]}^{2-}}\]

E)  None of these

Correct Answer: B

Solution :

                \[{{[Ni{{(CN)}_{4}}]}^{2-}}\] \[x-4=-\,2\]       \[x=4-2=+2\]       \[x=+\,2\] \[N{{i}^{2+}}={{d}^{8}}\] and \[C{{N}^{-}}\] is strong field ligand due to which pairing of electron occur. \[\therefore \,{{[Ni{{(CN)}_{4}}]}^{2-}}\]is diamagnetic.