Question

The spin-only magnetic moment value of an octahedral complex among $CoCl _{3} .4 NH _{3}$, $NiCl _{2} \cdot 6 H _{2} O$ and $PtCl _{4} \cdot 2 HCl$, which upon reaction with excess of $AgNO _{3}$ gives $2$ moles of $AgCl$ is ______B.M. (Nearest Integer)

Answer 1

$CoCl _{3} .4 NH _{3} \rightarrow\left[ Co \left( NH _{3}\right)_{4} Cl _{2}\right] Cl$
$NiCl _{2} \cdot 6 H _{2} O \rightarrow\left[ Ni \left( H _{2} O \right)_{6}\right] Cl _{2}$
$PtCl _{4} \cdot 2 HCl \rightarrow H _{2}\left[ PtCl _{6}\right]$
$\left[ Ni \left( H _{2} O \right)_{6}\right] Cl _{2} \xrightarrow{2 AgNO _{3}} 2 AgCl \downarrow+\left[ Ni \left( H _{2} O \right)_{6}\right]\left( NO _{3}\right)_{2}$

$\mu=\sqrt{2(2+2)}$ B.M $=2.84 \,BM \approx 3$