What is the oxidation number of chromium in the dimeric hydroxo bridged species?

Give the name describing the type of structural isomerism displayed by each of the following pairs;

$\left[\mathrm{Co}(\mathrm{en}{)}_3\right]\left[\mathrm{Cr}(\mathrm{CN}{)}_6\right]$ and $\left[\mathrm{Cr}(\mathrm{en}{)}_3\right]\left[\mathrm{Co}(\mathrm{CN}{)}_6\right]$

Give the name describing the type of structural isomerism displayed by each of the following pairs;

$\left[\mathrm{Mn}\left(\mathrm{CO}{)}_5\right(\mathrm{SCN})\right]$ and $\left[\mathrm{Mn}\left(\mathrm{CO}{)}_5\right(\mathrm{NCS})\right]$

Give the name describing the type of structural isomerism displayed by each of the following pairs;

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\left({\mathrm{NO}}_3\right)\right]{\mathrm{SO}}_4$ and $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_5\left({\mathrm{SO}}_4\right)\right]{\mathrm{NO}}_3$

Give the name describing the type of structural isomerism displayed by each of the following pairs,

$\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4\left({\mathrm{H}}_2\mathrm{O}\right)\mathrm{Cl}\right]{\mathrm{Cl}}_2$ and $\left[\mathrm{Co}{\left({\mathrm{NH}}_3\right)}_4{\mathrm{Cl}}_2\right]\mathrm{Cl}·{\mathrm{H}}_2\mathrm{O}$

${\mathrm{CoSO}}_4.\mathrm{Cl}.5{\mathrm{NH}}_3$ exists in two isomeric forms '$\mathrm{A}$' and '$\mathrm{B}$'. Isomer '$\mathrm{A}$' reacts with ${\mathrm{AgNO}}_3$ to give white precipitate, but does not react with ${\mathrm{BaCl}}_2.$ Isomer '$\mathrm{B}$' gives a white precipitate with ${\mathrm{BaCl}}_2$, but does not react with ${\mathrm{AgNO}}_3$. Identify '$\mathrm{A}$' and '$\mathrm{B}$' and write their structural formula.

${\mathrm{CoSO}}_4.\mathrm{Cl}.5{\mathrm{NH}}_3$ exists in two isomeric forms '$\mathrm{A}$' and '$\mathrm{B}$'. Isomer '$\mathrm{A}$' reacts with ${\mathrm{AgNO}}_3$ to give white precipitate, but does not react with ${\mathrm{BaCl}}_2.$ Isomer '$\mathrm{B}$' gives a white precipitate with ${\mathrm{BaCl}}_2$ , but does not react with ${\mathrm{AgNO}}_3$ .

Name the type of isomerism involved.