a
\(\mathrm{Cr}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6} \mathrm{Cl}_{\mathrm{n}}\)

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.