Question

Complex $X$ of composition $Cr\left(H_{2} O\right)_{6}\left(Cl\right)_{n}$ has a spin only magnetic moment of $3.83BM$ . It reacts with $AgNO_{3}$ and shows geometrical isomerism. The $IUPAC$ nomenclature of $X$ is

• A. Tetraaquadichlorido chromium (IV) chloride dihydrate
• B. Tetraaquadichlorido chromium (III) chloride dihydrate
• C. Hexaaqua chromium (III) chloride
• D. Dichloridotetraaqua chromium (IV) chloride dihydrate

Answer 1

Answer: (B)

This compound can be identified and named as follows
$Cr \left( H _{2} O \right)_{6} Cl _{ n }$
As $\left(\mu_{\text {complex }}\right)_{\text {spin }}=3.8 B \cdot M .=\sqrt{ n ( n +2)}$
On solving $n=3$
Oxidation No. of $\text{Cr} = + 3$
As compound also shows Geometrical isomerism so it will be $\left[\right.\text{Cr}H_{2} O \left._{4} \text{C} \text{l}_{2}\right]\text{Cl}.\text{2}\text{H}_{2}O$
It is named as $ \rightarrow $ Tetraaquadichloridochromium(III)chloride dihydrate