If ${\mathrm{Ni}}^{2+}$ is replaced by ${\mathrm{Pt}}^{2+}$ in the complex ${\left[{\mathrm{NiCl}}_2{\mathrm{Br}}_2\right]}^{2-}$, which of the following properties are expected to get changed?
A. Geometry
B. Geometrical isomerism
C. Optical isomerism
D. Magnetic properties

Consider the following complex ions, P, Q and R.

$\mathrm{P}={\left[{\mathrm{FeF}}_6\right]}^{3-},\mathrm{Q}={\left[\mathrm{V}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}, \mathrm{R}={\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$ 

The correct order of the complex ions, according to their spin-only magnetic moment values (in B.M.) is

Choose the complex, which is paramagnetic

(i) ${\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_6\right]}^{2+}$

(ii) ${\mathrm{K}}_3\left[\mathrm{Cr}{\left(\mathrm{CN}\right)}_6\right]$

(iii) ${\mathrm{K}}_3\left[\mathrm{Fe}{\left(\mathrm{CN}\right)}_6\right]$

(iv) ${\mathrm{K}}_2\left[\mathrm{Ni}{\left(\mathrm{CN}\right)}_4\right]$

Choose the correct statement(s) among the following: