JEE Main 2014 — Coordination Compounds Question with Solution

In both complexes Fe is in +3 oxidation state.
F^- ion  is weak field ligand so no pairing of electrons in inner 3d-orbitals & outer orbital complex. sp³d² hybridisation is formed.


have 5 unpaired electrons, so paramagnetic

${\mathrm{\mu }}_{{\left[{\mathrm{FeF}}_6\right]}^{-3}}=\sqrt{5(5+2)}=\sqrt{35 }\text{B}.\text{M}$
​​

One unpaired Electron, CN^- ion strong ligand field. So will pair the d-orbital electrons & form inner orbital hybridization d²sp³ .

${\text{μ}}_{{\left[\text{Fe}{\left(\text{CN}\right)}_6\right]}^{3-}}=\sqrt{1\left(1+2 \; \right)}$    (1 unpaired e^- so para magnetic)

                        $=\sqrt{3}B.M$.