Question

Amongst $FeCl _{3} .3 H _{2} O , K _{3}\left[ Fe ( CN )_{6}\right]$ and $\left[ Co \left( NH _{3}\right)_{6}\right] Cl _{3}$, the spin-only magnetic moment value of the inner-orbital complex that absorbs light at shortest wavelength is ____B.M. [nearest integer]

Answer 1

$\left[ Fe \left( H _{2} O \right)_{3} Cl _{3}\right], \underbrace{ K _{3}\left[ Fe ( CN )_{6}\right],\left[ Co \left( NH _{3}\right)_{6}\right] Cl _{3}}_{\text{inner orbital complexes}}$
$K _{3}\left[ Fe ( CN )_{6}\right]$ has more value of $\Delta_{0}$ than that of $\left[ Co \left( NH _{3}\right)_{6}\right] Cl _{3} ;$ as $\overline{ C } N$ is stronger ligand.

Spin only magnetic moment $(\mu)=\sqrt{3} BM$
$=1.732\, BM$
Rounding off $\Rightarrow 2$