The complexes given below show:

How many optical isomers are possible for the complex $[Pt(NH_3)_2(CN)_2]$?

Which of the following complexes exhibit geometrical isomerism?
$I$) $[Co(en)(NH_3)_2 Cl_2] Cl$
$II$) $[Co(NH_3)_4 Cl_2] Cl$
$III$) $[Co(en)_3] Cl_3$
$IV$) $[Co(en)_2 Cl_2] Br$

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

The magnetic moment of a transition element is $\sqrt{15} \, B.M.$ Determine the number of unpaired electrons present in it.

The number of paramagnetic metal complex species among $[Co(NH_3)_6]^{3+}$,$[Co(C_2O_4)_3]^{3-}$,$[MnCl_6]^{3-}$,$[Mn(CN)_6]^{3-}$,$[CoF_6]^{3-}$,$[Fe(CN)_6]^{3-}$ and $[FeF_6]^{3-}$ with the same number of unpaired electrons is $............$