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

The volume of $1$ mole of any pure gas at standard temperature and pressure $(STP)$ is always equal to (in $m^3$)

Which one of the following statements is wrong for gases?

$A$ sample of $N_2$ gas at $0.8 \, atm$ pressure takes $38 \, s$ to effuse through a pinhole. $A$ sample of $1 \, mol$ of an unknown gas '$X$' at $1.6 \, atm$ pressure takes $57 \, s$ to effuse through the same pinhole. The molar mass of gas '$X$' in $g/mol$ is .............

$A$ gaseous mixture contains equal masses of dihydrogen gas,dioxygen gas and methane gas at a total pressure of $380 \ torr$. The partial pressure of methane gas is ........... $torr$.

The water having more dissolved $O_{2}$ is: