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 $AgN{O}_3$ 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
$Cr{\left(H_{2}O\right)}_{6}C{l}_n$
As ${\left({\mu }_{\text{complex }}\right)}_{\text{spin }}=3.8B\cdot M.=\sqrt{n(n+2)}$
On solving $n=3$
Oxidation No. of $\text{Cr}=+3$
As compound also shows Geometrical isomerism so it will be $[\text{Cr}{H}_{2}O{}_4\text{C}{\text{l}}_2]\text{Cl}.\text{2}{\text{H}}_{2}O$
It is named as $\to$ Tetraaquadichloridochromium(III)chloride dihydrate