Who among the following scientists has not done any important work on gases?

If $P_1$ is the partial pressure of a gas and $x_1$ is its mole fraction in a mixture,then the correct relation between $P_1$ and $x_1$ is:

$A$ 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?

$A$ bulb contains $1 \ g$ of $H_2$ and $1 \ g$ of $He$. If the total pressure is $1.2 \times 10^3 \ Pa$,then the partial pressure of $He$ is ............. $Pa$.

The ratio of rates of diffusion of oxygen and an unknown gas is $1:4$. The unknown gas is

The interaction energy of $London$ forces between two particles is proportional to $r^{x}$,where $r$ is the distance between the particles. The value of $x$ is: