If the most probable speed of $CO_2$ at $27^{\circ} C$ is $400 \ ms^{-1}$,the root mean square velocity of $CO_2$ at the same temperature in $ms^{-1}$ is approximately:

At $T$ $(K)$,the $P$,$V$ and $u_{rms}$ of $1$ mole of an ideal gas were measured. The following graph is obtained. What is its slope $(m)$? ($x$-axis $= PV$; $y$-axis $= u_{rms}^2$,$M =$ Molar mass)

At a given temperature,which gas will have a higher speed between $H_2$ and $O_2$? Why?

Predict the correct order of rate of diffusion of the following molecules.

If $r_1, r_2$ and $r_3$ represent the most probable speeds of three different gases at the same temperature as shown in the figure,with molar masses $M_1, M_2$ and $M_3$ respectively,what is the correct order of the molar masses of these gases?

The gas that has the slowest rate of diffusion among $O_2$,$H_2$,$CO_2$ and $CH_4$ is