How many of the following molecules have two lone pairs of electrons on central atom?

$\mathrm{SF}_6, \mathrm{BF}_3, \mathrm{ClF}_3, \mathrm{PCl}_5, \mathrm{BrF}_5, \mathrm{XeF}_4, \mathrm{H}_2 \mathrm{O}, \mathrm{SF}_4$

The pair of molecules / ions with the same bond order value is

At what temperature (in K ) the rms velocity of $\mathrm{SO}_2$ molecules is equal to rms velocity of $\mathrm{O}_2$ molecules at $27^{\circ} \mathrm{C}$ ?

For one mole of an ideal gas an isochore is obtained. The slope of the isochore is $0.082 \mathrm{~atm} \mathrm{~K}^{-1}$. What will be its pressure (in atm) when the temperature is $12.2 \mathrm{~K} ?\left(R=0.082 \mathrm{~L} \mathrm{~atm} \mathrm{~mol}^{-1} \mathrm{~K}^{-1}\right)$