Note: In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

Assertion: [Fe(CN)6]3– ion shows magnetic moment corresponding to twounpaired electrons.


Reason: Because it has d2sp3 type hybridisation.


The assertion is false butthe reason is true.


For [Fe(CN)6]4– the central metal atom is Fe and its oxidation state is x=-6 times(-1)-4=+2.


Hence, it has a d6 configuration (1s2 2s2 2p6 3s2 3p6 3d6) and as it is left with 2 empty 3d orbitals and 1 empty 4s orbital which in interaction with 3,4p orbitals and attain the hybridisation d2sp3 and the 6 CN- electrons will occupy these 6 hybridised orbitals. And the hybridisation scheme will be:1.PNG


And the orbital energy level diagram is:



which clearly shows that it has no unpaired electrons as CN- is strong field ligand and the energy gap becomes larger, therefore [Fe(CN)6]4– ion is diamagnetic and therefore shows no magnetic because of the absence of unpaired electrons.

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