Which of the following relations is true based on the partial pressure and mole fraction?

The rate of diffusion of a gas is directly proportional to ....

Under the same conditions of pressure and temperature,the same volume of two gases $A$ and $B$ diffuse through a porous partition in $20 \ s$ and $10 \ s$ respectively. The molecular mass of $A$ is $49 \ u$. The molecular mass of $B$ will be ............. $u$.

If some moles of $O_2$ diffuse in $18 \ sec$ and the same moles of another gas diffuse in $45 \ sec$,what is the molecular weight of the unknown gas?

$50 \ mL$ of hydrogen gas diffuses through a small hole in a container in $20 \ min$. How much time (in $min$) will $40 \ mL$ of oxygen take to diffuse under the same conditions?

The ratio of the rate of diffusion of $SO_2$ to $CH_4$ is