Which of the following mixtures of gases at room temperature does not obey Dalton's law of partial pressure?

The rate of diffusion of methane at $1.0 \ atm$ pressure is twice that of another gas '$X$' kept at $1.45 \ atm$. The molecular weight of the gas '$X$' is
[$T$ kept constant]

$A$ gas sample of $1.47 \ L$ was collected over water at $30 \ ^\circ C$ and $744 \ mm \ Hg$ pressure. If the weight of the gas is $1.98 \ g$,what is the molar mass of the gas? (Assume the vapor pressure of water at $30 \ ^\circ C$ is $31.8 \ mm \ Hg$)

If the rate of diffusion of a gas having twice the molecular mass of nitrogen is $56 \ mL \ s^{-1}$,then the rate of diffusion of nitrogen will be ........... $mL \ s^{-1}$.

Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen escapes in the time required for one-half of the hydrogen to escape?

Mixing of two different ideal gases under isothermal reversible conditions will lead to: