if magnetic mement is 3.83 BM then it contain three unpaired electrons. It means chromium in $+3$ oxidation state so molecular formula is

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

This formula have following isomers

(a) $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{3}:$ react with $\mathrm{AgNO}_{3}$ but does not show geometrical isomerism.

(b) $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{5} \mathrm{Cl}\right] \mathrm{Cl}_{2} \cdot \mathrm{H}_{2} \mathrm{O}$ react with $\mathrm{AgNO}_{3}$ but does not show geometrical isomerism.

(c) $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl} .2 \mathrm{H}_{2} \mathrm{O}$ react with $\mathrm{AgNO}_{3}$ and show geometrical isomerism.

(d) $\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{3} \mathrm{Cl}_{3}\right] .3 \mathrm{H}_{2} \mathrm{O}$ does not react with $\mathrm{AgNO}_{3}$ and show geometrical isomerism.

$\left[\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{4} \mathrm{Cl}_{2}\right] \mathrm{Cl} .2 \mathrm{H}_{2} \mathrm{O}$ react with $\mathrm{AgNO}_{3}$ and show geometrical isomerism and it's IUPAC nomenclature is $\quad$ Tetraaquadichlorido chromium (III) Chloride dihydrate.