The ratio of the rate of diffusion of a given element to that of helium is $1.4$. The molecular weight of the element is

$A$ mixture of one mole each of $H_2$,$He$ and $O_2$ are enclosed in a cylinder of volume $V$ at temperature $T$. If the partial pressure of $H_2$ is $2 \ atm$,the total pressure of the gases in the cylinder is $....... \ atm$

$A$ container contains equal masses of $H_2$,$He$,$CO_2$,and $Ne$ at a certain temperature. Which of the following gases exerts minimum partial pressure?

During the evaporation of a liquid,the temperature of the liquid ..

In a container,the mole ratio of two gases $A$ and $B$ is $2 : 5$. The total pressure of the container is $3.5 \times 10^5 \ Pa$. If all molecules of $A$ are removed from the container,what will be the pressure exerted by the molecules of $B$?

The pressure under which liquid and vapour can coexist at equilibrium is called the