Solid $CO_2$ is known as dry ice,because

$A$ mixture of $He$ and $CH_4$ in a molar ratio of $4:1$ is present in a container at a pressure of $20 \ bar$. Due to a hole in the container,the gas mixture leaks out. What will be the composition of the gas mixture effusing out initially (in $: 1$)?

$A$ tube of length $1 \, m$ has identical pinholes at both ends. Ammonia gas at $1 \, atm$ pressure is introduced from one end,and $HCl$ gas at $P \, atm$ pressure is introduced from the other end at room temperature. If $NH_4Cl$ is formed at a distance of $60 \, cm$ from the end where $HCl$ was introduced,calculate the value of pressure $P$. (in $, atm$)

Two thin circular discs $A$ and $B$ of radii $2 \ cm$ and $4 \ cm$ are in a liquid at the same depth. $T_A$ is the thrust on $A$ and $T_B$ is the thrust on $B$. Then $T_A : T_B =$

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.

What is the ratio of kinetic energies of $3 \ g$ of hydrogen and $4 \ g$ of oxygen at a certain temperature?