If $4 \ g$ of oxygen diffuses through a narrow hole under identical conditions,how many grams of hydrogen will diffuse?

Which of the following graphs is incorrect?

The graph shows the characteristics of one mole of an ideal gas at a pressure of $1 \ atm$ with respect to volume $(V)$ and temperature $(T)$. Identify the correct graph.

An empty $LPG$ cylinder weighs $14.8 \ kg$. When full,it weighs $29.0 \ kg$ and shows a pressure of $3.47 \ atm$. In the course of use at ambient temperature,the mass of the cylinder is reduced to $23.0 \ kg$. The final pressure inside of the cylinder is $....... \ atm$. (Nearest integer)
(Assume $LPG$ to be an ideal gas)

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 $mm$?

When the temperature is raised,the viscosity of liquid decreases,this is because