Equal masses of three non-reacting different ideal gases $X, Y$ and $Z$ are mixed in a sealed rigid container. If the temperature of the system remains constant at $400 \ K$,which of the following statements about gas $X$ can never be correct?

Solid $CO_2$ is known as dry ice,because

$A$ fixed mass '$m$' of a gas is subjected to a transformation of states from $K$ to $L$ to $M$ to $N$ and back to $K$ as shown in the figure.
$1.$ The succeeding operations that enable this transformation of states are:
$(A)$ Heating,cooling,heating,cooling
$(B)$ Cooling,heating,cooling,heating
$(C)$ Heating,cooling,cooling,heating
$(D)$ Cooling,heating,heating,cooling
$2.$ The pair of isochoric processes among the transformation of states is:
$(A)$ $K$ to $L$ and $L$ to $M$
$(B)$ $L$ to $M$ and $N$ to $K$
$(C)$ $L$ to $M$ and $M$ to $N$
$(D)$ $M$ to $N$ and $N$ to $K$
Give the answer for question $1$ and $2$.

When $0.0168 \, mol$ of $O_2$ obtained from the decomposition of $KClO_3$ is collected over water at $25 \, ^\circ C$,the volume is $428 \, mL$ and the pressure is $754 \, mm$. What is the water vapor pressure at $25 \, ^\circ C$ in $mm$?

$A$ vessel of volume $1.2 \, L$ contains a gas at $1000 \, torr$ pressure. Another vessel of volume $3.8 \, L$ contains the same gas at $500 \, torr$ pressure. If both vessels are connected by a tube of negligible volume,what will be the resultant pressure in $torr$ when equilibrium is established?

Which of the following statements is incorrect?
$1$. The property of liquid drops to have minimum surface area is called surface tension.
$2$. Surface tension of liquids decreases with rise in temperature.
$3$. The $SI$ unit of surface tension is $N \ m^{-1}$.
$4$. Magnitude of surface tension is less,when there is strong attractive force between the molecules.