The number of unpaired electrons responsible for the paramagnetic nature of the following complex species are respectively :

[Fe(CN)₆]³⁻, [FeF₆]³⁻, [CoF₆]³⁻, [Mn(CN)₆]³⁻

'X' is the number of acidic oxides among VO₂, V₂O₃, CrO₃, V₂O₅ and Mn₂O₇. The primary valency of cobalt in
[Co(H₂NCH₂CH₂NH₂)₃]₂(SO₄)₃ is Y. The value of X + Y is _________.

An octahedral complex having molecular composition $\mathrm{Co} \cdot 5 \mathrm{NH}_3 \cdot \mathrm{Cl}^2 . \mathrm{SO}_4$ has two isomers A and B. The solution of A gives a white precipitate with $\mathrm{AgNO}_3$ solution and the solution of B gives white precipitate with $\mathrm{BaCl}_2$ solution. The type of isomerism exhibited by the complex is,

' $X$ ' is the number of electrons in $t_{2 g}$ orbitals of the most stable complex ion among $\left[\mathrm{Fe}\left(\mathrm{NH}_3\right)_6\right]^{3+},\left[\mathrm{FeCl}_6\right]^{3-}, \quad\left[\mathrm{Fe}\left(\mathrm{C}_2 \mathrm{O}_4\right)_3\right]^{3-}$ and $\left[\mathrm{Fe}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{3+}$. The nature of oxide of vanadium of the type $\mathrm{V}_2 \mathrm{O}_{\mathrm{X}}$ is :