Select the correct statement(s) with respect to an octahedral complex having $\mathrm{CFSE}=-1.2 {∆}_0$.

(a) The compound is neither low spin nor high spin complex.

(b) The type of hybridization in complex does not depend upon the nature of ligands.

(c) Magnetic moment of a complex compound is either $\sqrt{15} \mathrm{BM}$ or $\sqrt{8} \mathrm{BM}$.

 

 An octahedral complex $\text{'}\mathrm{X}\text{'}$ with magnetic moment $3.87 \mathrm{BM}$ may have:

(a) ${\mathrm{d}}^3$ configuration with weak field ligand.

(b) ${\mathrm{d}}^3$ configuration with strong field ligand.

(c) ${\mathrm{d}}^6$ configuration with strong field ligand.

(d) ${\mathrm{d}}^7$ configuration with weak field ligand.

The complex ${\left[\mathrm{Fe}{\left({\mathrm{H}}_2\mathrm{O}\right)}_5\mathrm{NO}\right]}^{+2}$ is formed in a brown ring test for nitrates when the freshly prepared ${\mathrm{FeSO}}_4$ solution is added to an aqueous solution of ${\mathrm{NO}}_3^{-}$ followed by the addition of concentrated ${\mathrm{H}}_2{\mathrm{SO}}_4.$ Which statements are correct about this complex?

$\left(\mathrm{a}\right)$ Colour of the complex is due to the charge transfer.

$\left(\mathrm{b}\right)$ Both iron and nitrosonium have $+1$ oxidation state.

$\left(\mathrm{c}\right)$ Electronic configuration of the central metal is $\left[\mathrm{Ar}\right] 3{\mathrm{d}}^{6}4{\mathrm{s}}^1$.

A metal complex having composition $\mathrm{Cr}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{IBr}}_2$, was isolated in two forms $\mathrm{X}$ and $\mathrm{Y}$($\mathrm{Br}$ is bromine and $\mathrm{I}$ is iodine).

(a) $\mathrm{X}$ reacts with ${\mathrm{AgNO}}_3$ and gives a pale yellow precipitate which is insoluble in ${\mathrm{NH}}_4\mathrm{OH}$.

(b) $\mathrm{Y}$ reacts with ${\mathrm{AgNO}}_3$ and gives a yellow precipitate which is insoluble in ${\mathrm{NH}}_4\mathrm{OH}$.

$\mathrm{I}$. Ionisation

$\mathrm{II}$. Hydrate

$\mathrm{III}$. Coordination

$\mathrm{IV}$. Geometrical

$\mathrm{V}$. Optical

Which of the above isomerisms are exhibited by ${\left[\mathrm{Cr}{\left({\mathrm{NH}}_3\right)}_2{\left(\mathrm{OH}\right)}_2{\mathrm{Cl}}_2\right]}^{-1}$?