The rate of diffusion of $SO_3$,$CO_2$,$PCl_3$ and $SO_2$ gases are in the following order:

In a container,the mole ratio of two gases $A$ and $B$ is $2 : 5$. The total pressure of the container is $3.5 \times 10^5 \ Pa$. If all molecules of $A$ are removed from the container,what will be the pressure exerted by the molecules of $B$?

Fill in the blanks:
$(1)$ The properties of gases were first measured by ......... .
$(2)$ The dipole-dipole interaction energy between stationary polar molecules is proportional to .......... .
$(3)$ The interaction energy between rotating polar molecules is proportional to .......... .
$(4)$ The bond energy of a hydrogen bond is about ......... $kJ \ mol^{-1}$.

What is the density of water vapour at the boiling point of water?

At higher altitudes,the boiling point of water lowers because:

Two grams of hydrogen diffuse from a container in $10 \ min$. How many grams of oxygen would diffuse through the same container in the same time under similar conditions?