$\therefore \text { Unpaired } e ^{-}=5$

$\mu=\sqrt{ n ( n +2)}$

$=\sqrt{5(5+2)}$

$\mu=\sqrt{35}=5.92 \text { B.M. }$

${\left[ Fe ( CN )_6\right]^{-3}}$

Pairing occur due to strong field ligand $CN ^{-}$

$\therefore$ Unpaired $e^-$ $\Rightarrow 1$

$\mu=\sqrt{ n ( n +2)}$

$=\sqrt{1(1+2)}=\sqrt{3}=1.732 \text { B.M. }$