The rate of diffusion of methane $(CH_4)$ at a given temperature is twice that of gas $X$. The molecular weight of gas $X$ is:

$A$ person living in $Manali$ observed that cooking food without using a pressure cooker takes more time. The reason for this observation is that at high altitude:

Four rubber tubes are filled with $H_2, O_2, N_2$,and $He$ respectively. Which of these tubes will deflate first?

The rate of diffusion of a gas (molar mass = $128$) compared to oxygen is:

$A$ sample of $O_2$ gas is collected over water at $23\,^oC$ at a barometric pressure of $751\, mm\, Hg$ (vapour pressure of water at $23\,^oC$ is $21\, mm\, Hg$). The partial pressure of $O_2$ gas in the sample collected is

$80 \ mL$ of $O_2$ takes $2 \ minute$ to pass through the hole. What volume of $SO_2$ will pass through the hole in $3 \ minute$?