Observe the following list of molecules. Number of polar and non-polar molecules are respectively

$\mathrm{NH}_3, \mathrm{BF}_3, \mathrm{NF}_3, \mathrm{H}_2 \mathrm{~S}_2, \mathrm{CO}_2, \mathrm{CH}_4, \mathrm{CHCl}_3, \mathrm{H}_2 \mathrm{O}$

The molecule ' $X$ ' has see-saw shape with central atom in $s p^3 d$ hybridisation. What is ' $X$ '?

Identify the pair of molecules in which the hybridisation of the central atom is $s p^2$ with bent geometry.

Consider the following statements

I. In the conversion of $\mathrm{O}_2$ to $\mathrm{O}_2^{2+}$ bond order decreases.

II. In the conversion of $\mathrm{O}_2$ to $\mathrm{O}_2^{2+}$ magnetic property is not changed.

III. In the conversion of $\mathrm{O}_2$ to $\mathrm{O}_2^{2+}$ bond length decreases.

IV. $\mathrm{O}_2^{2-}$ and $\mathrm{B}_2$ have same bond order.

Identify the correct statements