If $4 \ g$ of oxygen gas diffuses through a fine hole,how many grams of hydrogen gas will diffuse under the same conditions?

Ice and water are placed in a closed container at a pressure of $1 \ atm$ and temperature $273.15 \ K$. If the pressure of the system is increased $2$ times,keeping the temperature constant,then identify the correct observation from the following:

The combination of plots which do not represent isothermal expansion of an ideal gas is

$A$ 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 $: 1$)?

$60 \ cm^3$ of $SO_2$ gas diffused through a porous membrane in '$x$' min. Under similar conditions $360 \ cm^3$ of another gas (molar mass $4 \ g \ mol^{-1}$) diffused in '$y$' min. The ratio of $x$ and $y$ is

Why does a sharp glass edge become smooth on heating it up to its melting point in a flame? Explain which property of liquids is responsible for this phenomenon.