$A$ mixture of equal masses of $SO_2$,$CH_4$,and $O_2$ is taken in an empty container at $298 \, K$. If the total pressure is $2.1 \, atm$,the partial pressure of $CH_4$ in the mixture will be .......... $atm$.

The rate of diffusion of methane at $1.0 \ atm$ pressure is twice that of another gas '$X$' kept at $1.45 \ atm$. The molecular weight of the gas '$X$' is
[$T$ kept constant]

Equal amounts of two gases of molecular weight $4$ and $40$ are mixed. The pressure of the mixture is $1.1 \, atm$. The partial pressure of the light gas in this mixture is ........... $atm$.

Explain the fire polishing of glass.

Based on the given figure,the number of correct statement/s is/are $........$.
$A.$ Surface tension is the outcome of equal attractive and repulsion forces acting on the liquid molecule in bulk.
$B.$ Surface tension is due to uneven forces acting on the molecules present on the surface.
$C.$ The molecule in the bulk can never come to the liquid surface.
$D.$ The molecules on the surface are responsible for vapour pressure if the system is a closed system.

The variation of pressure with volume of a gas at different temperatures can be graphically represented as shown in the figure. On the basis of this graph,answer the following questions:
$(i)$ How will the volume of a gas change if its pressure is increased at constant temperature?
$(ii)$ At a constant pressure,how will the volume of a gas change if the temperature is increased from $200 \ K$ to $400 \ K$?