Three layers of liquid are flowing over a fixed solid surface as shown below. The correct order of velocity of the liquid in these layers is:

Identify the correct statements from the following.
$I$. Glass is an extremely viscous liquid.
$II$. Increase in temperature decreases the surface tension of liquids.
$III$. Compressibility factor for an ideal gas is zero.

Two gases $X$ and $Y$ are taken in equal molar proportions. The ratio of their rates of diffusion is $1 : 2$. What will be the mole fraction of $X$ in a mixture containing $2 \ g$ of $X$ and $3 \ g$ of $Y$?

$A$ 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 $31.8 \ mm \ Hg$)

Liquids flow from a higher level to a lower level. Which of the following liquids climbs up the walls of a glass vessel when filled in it?

The correct value of the universal gas constant $R$ is: