Two balloons $A$ and $B$ containing $0.2 \ mol$ and $0.1 \ mol$ of helium at room temperature and $2.0 \ atm$,respectively,are connected. When equilibrium is established,the final pressure of $He$ in the system is $.... \ atm$.

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.

Which of the following gas mixtures is not applicable for Dalton's law of partial pressure?

Assertion : We feel cold on touching the ice.
Reason : Ice is a solid form of water.

Equal weights of $CH_4$ and $H_2$ are mixed in an empty container at $25 \, ^oC$. The fraction of the total pressure exerted by $H_2$ would be

Two flasks $I$ and $II$ shown below are connected by a valve of negligible volume. When the valve is opened,the final pressure of the system in bar is $x \times 10^{-2}$. The value of $x$ is $.....$ . (Integer answer) [Assume-Ideal gas; $1 \, bar = 10^{5} \, Pa$; Molar mass of $N_{2} = 28.0 \, g \, mol^{-1}$; $R = 8.31 \, J \, mol^{-1} \, K^{-1}$]