Which one of the following statements best describes the acidic/basic/amphoteric nature of ZnO and CaO ?

Which among the following processes is/are associated with increasing bond order but no change in diamagnetic/paramagnetic behaviour?

(i) $\mathrm{N}_2 \rightarrow \mathrm{~N}_2^{+}+\mathrm{e}^{-}$

(ii) $\mathrm{O}_2 \rightarrow \mathrm{O}_2^{+}+\mathrm{e}^{-}$

(iii) $\mathrm{O}_2+\mathrm{e}^{-} \rightarrow \mathrm{O}_2^{-}$

What is the value of $E^{\circ}\left(\mathrm{Fe}^{3+} / \mathrm{Fe}^0\right)$ ?

[The standard reduction potential values are $E^{\circ}\left(\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}\right)=0.77 \mathrm{~V}$, and $\left.E^{\circ}\left(\mathrm{Fe}^{2+} / \mathrm{Fe}^0\right)=-0.44 \mathrm{~V}\right]$

$$ \text { What are the correct orders of stability for the following compounds? } $$