Gas $X$ diffuses three times faster than gas $Y$. What is the ratio of their densities,i.e.,$D_x : D_y$?

$A$ mixture of $0.5 \text{ mol}$ $N_2$ gas, $1.0 \text{ mol}$ $O_2$ gas and $1.5 \text{ mol}$ $H_2$ gas exerts a total pressure of $18 \text{ bar}$. Find the partial pressure of $O_2(g)$. (in $\text{ bar}$)

What will be the pressure at $0\,^oC$ in Kolkata,Chennai,and Mumbai (in $,bar$)?

Normal boiling point of water is $373 \ K$ (at $760 \ mm$). Vapour pressure of water at $298 \ K$ is $23 \ mm$. If the enthalpy of evaporation is $40.656 \ kJ/mole$,the boiling point of water at $23 \ mm$ pressure will be ............. $K$.

The rate of diffusion of a gas $A$ is $\sqrt{5}$ times more than that of gas $B$. If the molar mass of $A$ is $x \ g \ mol^{-1}$, the molar mass of $B \ (\text{in } g \ mol^{-1})$ is (in $x$)

During the evaporation of a liquid: