Co-Ordination Compounds Question 116
Question: Amongst $ Ni{{( CO )}_4}, $ $ {{[ Ni{{(CN)}_4} ]}^{2-}} $ and $ {{[NiCl_4]}^{2-}} $
[IIT 1991]
Options:
A) $ Ni{{( CO )}_4} $ and $ {{[ NiCl_4 ]}^{2-}} $ are diamagnetic and $ {{[Ni{{(CN)}_4}]}^{2-}} $ is paramagnetic
B) $ {{[ NiCl_4 ]}^{2-}} $ and $ {{[ Ni{{( CN )}_4} ]}^{2-}} $ are diamagnetic and $ Ni{{( CO )}_4} $ is paramagnetic
C) $ Ni{{( CO )}_4} $ and $ {{[ Ni{{( CN )}_4} ]}^{2-}} $ are diamagnetic and $ {{[ NiCl_4 ]}^{2-}} $ is paramagnetic
D) $ Ni{{( CO )}_4} $ is diamagnetic and $ {{[ NiCl_4 ]}^{2-}} $ and $ {{[ Ni{{( CN )}_4} ]}^{2-}} $ are paramagnetic
Show Answer
Answer:
Correct Answer: C
Solution:
The electronic configuration of Ni in $ {{[Ni{{(CN)}_4}]}^{2-}},,{{[Ni(Cl_4)]}^{2-}} $ and $ Ni{{(CO)}_4} $ are as following $ N{i^{+}} $ in $ {{[Ni{{(CN)}_4}]}^{2-}} $ - $ N{i^{2+}} $ in $ {{[Ni(Cl_4)]}^{2-}} $ - $ Ni $ in $ [Ni{{(CO)}_4}] $ - CO and $ C{N^{-}} $ are strong ligands so they induces pairing of electrons so their complexes are diamagnetic while $ C{l^{-}} $ is a weak ligand so it does not induce the pairing of electrons so its complex is paramagnetic.
