Amongst FeCl 3 . 3 H 2 O , K 3 Fe CN 6 and Co NH 3 6 Cl 3 , the spin-only magnetic moment value of the inner-orbital complex that absorbs light at shortest wavelength is B.M. [nearest integer]

Step-by-step solution

Complex EC Hybridisation No. of unpaired e - (i) FeCl 3 · 3 H 2 O Fe 3 + = 3   d 5 sp 3 d 2 5 (ii) K 3 Fe CN 6 Fe 3 + = 3   d 5 d 2 sp 3 1 (iii) Co NH 3 6 3 + Co 3 + = 3   d 6 d 2 sp 3 0 CN - is strong ligand than NH 3 so splitting in K 3 [ Fe CN 6 ] is higher and it absorb light of shortest wave length μ spin only = n n + 2 = 3 = 1 . 73 BM ≈ 2 BM