[Fe(SCN)6]3−and[Fe(CN)6]3− In both the cases the electronic configuration of Fe3+ will be 1s2,2s2,2p6,3s2,3p6,3d5 Since SCN is a week field ligand and CN is a strong field ligand the pairing will occur only in case of [Fe(CN)6]3−
Case -1 μ=√n(n+2)=√5(5+2)=√35=5.91BM Case -2 μ=√n(n+2)=√1(1+2)=√3=1.73BM
Difference in sin only magnetic momnet =5.91-1.73=4.18 ≈ 4