The vapor pressure of water at $80\,^oC$ is $355.5\, mm\, of\, Hg$. $A$ $100\, mL$ vessel contains $O_2$ saturated with water vapor at $80\,^oC$,and the total pressure is $760\, mm\, of\, Hg$. If the contents are transferred to a $50\, mL$ vessel at the same temperature,what will be the partial pressure of $O_2$ in $mm\, Hg$?

Identify the incorrect statement among the following:

$A$ 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 $31.8 \ mm \ Hg$)

Two thin circular discs $A$ and $B$ of radii $2 \ cm$ and $4 \ cm$ are in a liquid at the same depth. $T_A$ is the thrust on $A$ and $T_B$ is the thrust on $B$. Then $T_A : T_B =$

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.

The variation of pressure with volume of a gas at different temperatures can be graphically represented as shown in the figure. On the basis of this graph,answer the following questions:
$(i)$ How will the volume of a gas change if its pressure is increased at constant temperature?
$(ii)$ At a constant pressure,how will the volume of a gas change if the temperature is increased from $200 \ K$ to $400 \ K$?