Improve silver ore $+\mathrm{CN}^{-}+\mathrm{H}_2 \mathrm{O} \xrightarrow{\mathrm{O}_2}[\mathrm{X}]^{-}+\mathrm{OH}^{-}$

$$ [X]^{-}+\mathrm{Zn} \longrightarrow[Y]^{2-}+\mathrm{Ag} \text { (pure) } $$

The co-ordination numbers of the metals in $[X]$. [ $Y$ ] are respectively

How many of the following ligands are stronger than

$$ \begin{aligned} & \mathrm{H}_2 \mathrm{O} \text { ? } \\ & \mathrm{S}^{2-}, \mathrm{Br}^{-}, \mathrm{C}_2 \mathrm{O}_4^{2-}, \mathrm{CN}^{-} \text {, en, } \mathrm{NH}_3, \mathrm{CO}, \mathrm{OH}^{-} \\ & \begin{array}{ll} \text { } & \text { } \end{array} \end{aligned} $$

Arrange the following in the increasing order of number of unpaired electrons present in the central metal ion

I. $\left[\mathrm{MnCl}_6\right]^{3-}$

II. $\left[\mathrm{FeF}_6\right]^{3-}$

III. $\left[\mathrm{Mn}(\mathrm{CN})_6\right]^{3-}$

IV. $\left[\mathrm{Fe}(\mathrm{CN})_6\right]^{3-}$