If a didentate ligand ethane-1, 2-diamine is progressively added in the molar ratio en : Ni :: 1: 1, 2 : 1, 3 : 1 to $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right]^{2+}$$ aq solution, following co-ordination entities are formed.

I. $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{en}\right]^{2+}(a q)$$ - pale blue

II. $$\left[\mathrm{Ni}\left(\mathrm{H}_2 \mathrm{O}\right)_2(\mathrm{en})_2\right]^{2+}(\mathrm{aq})$$ - blue/purple

III. $$\left[\mathrm{Ni}(\mathrm{en})_3\right]^{2+}(\mathrm{aq})$$ - violet

The wavelength in $$\mathrm{nm}$$ of light absorbed in case of I and III are respectively

Which of the following is an organometallic compound

When $$\mathrm{FeCl}_3$$ is added to excess of hot water gives a sol '$$X$$'. When $$\mathrm{FeCl}_3$$ is added to $$\mathrm{NaOH}(a q)$$ solution, gives sol '$$Y$$'

$$X$$ and $$Y$$ formed in the above processes respectively are

Which formula and name combination is incorrect?