$\therefore \text { Unpaired } e ^{-}=5$
$\mu=\sqrt{ n ( n +2)}$
$=\sqrt{5(5+2)}$
$\mu=\sqrt{35}=5.92 \text { B.M. }$
${\left[ Fe ( CN )_6\right]^{-3}}$
Pairing occur due to strong field ligand $CN ^{-}$
$\therefore$ Unpaired $e^-$ $\Rightarrow 1$
$\mu=\sqrt{ n ( n +2)}$
$=\sqrt{1(1+2)}=\sqrt{3}=1.732 \text { B.M. }$