For any pure liquid at a pressure of $1.013 \ bar$,the temperature at which the liquid and vapor are at equilibrium is called:

$A$ closed vessel contains an equal number of molecules of $N_2$ and $O_2$ at a pressure of $650 \ mm$. If $N_2$ is completely removed,what will be the pressure in the vessel?

$X \ mL$ of $H_2$ gas effuses through a hole in a container in $5 \ s$. The time taken for the effusion of the same volume of the gas specified below under identical conditions is:

Sulphur dioxide $(SO_2)$ and oxygen $(O_2)$ were allowed to diffuse through a porous partition. $20 \ dm^3$ of $SO_2$ diffuses through the porous partition in $60 \ seconds$. The volume of $O_2$ in $dm^3$ which diffuses under the similar conditions in $30 \ seconds$ will be (atomic mass of sulphur $= 32 \ u$)

The density of a gas at $STP$ is $2.86 \, g \, L^{-1}$. Which gas is it?

Gaseous state is characterised by which of the following physical properties?
$I$. Gases mix evenly and completely in all proportions without any mechanical aid.
$II$. Gases exert pressure in all directions evenly.
$III$. Gases are highly compressible and have lower density than liquids and solids.
$IV$. The volume and shape of the gas is fixed.