# Complex X of composition

Question:

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

1. Â Hexaaqua chromium (III) chloride

2. Tetraaquadichlorido chromium (IV) chloride dihydrate

3. Â Dichloridotetraaqua chromium (IV) chloride dihydrate

4. Tetraaquadichlorido chromium (III) chloride dihydrate

Correct Option: , 4

Solution:

$\mu=\sqrt{n(n+2)}$ B.M. $=3.83$ B.M.

$n=3\left(n=\right.$ No. of unpaired $\left.e^{-}\right)$

Therefore, oxidation number of $\mathrm{Cr}$ should be $+3$.

Hence complex is $\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6} \mathrm{Cl}_{3}$.

Complex shows geometrical isomerism therefore formula of complex is $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl} .2 \mathrm{H}_{2} \mathrm{O}$.

IUPAC Name: