What type of isomerism is exhibited by $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$ and $\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2 \cdot \mathrm{H}_2 \mathrm{O}$

Identify heteroleptic complex from following.

What is the oxidation state of central metal ion in $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{4-}$ complex?

Which from following is a formula of sodium hexafluoroaluminate(III)?