The ratio of the rate of diffusion of helium and methane under identical conditions of pressure and temperature will be

$A$ gaseous mixture was prepared by taking equal moles of $CO$ and $N_2$. If the total pressure of the mixture was found to be $1 \ atm$,the partial pressure of the nitrogen $(N_2)$ in the mixture is $...$ $atm$.

$A$ container contains $5 \ mol$ of $A$ and $10 \ mol$ of $B$. The total pressure of the container is $18 \ atm$. What are the partial pressures $P_A$ and $P_B$ respectively?

Write the formula to calculate the pressure of a dry gas collected over water.

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 ............. $u$.

$A$ certain volume of oxygen gas diffuses through a porous pot in $20 \ s$. If the same volume of another gas $(X)$ diffuses in $Y \ s$, then $(X)$ and $Y$ respectively are: