From the following $P-T$ graph,what inference can be drawn?

The quantity $\frac{PV}{kT}$ represents ($k=$ Boltzmann constant).

$O_2$ gas is filled in a vessel. If the pressure is doubled and the temperature becomes four times,how many times will its density become?

$A$ gas has a volume $V$ at a temperature of $27^{\circ}C$. If the temperature is increased to $327^{\circ}C$ while keeping the pressure constant,what will be the new volume of the gas?

$A$ container holds $6 \ g$ of oxygen at a pressure $P$ and temperature $400 \ K$. $A$ small hole is made in the container so that oxygen can leak out. How much oxygen (in $g$) will leak out by the time the pressure becomes $P/2$ and the temperature becomes $300 \ K$?

The figure shows two flasks connected to each other. The volume of flask $1$ is twice that of flask $2$. The system is filled with an ideal gas at temperatures $100\, K$ and $200\, K$ respectively. If the mass of the gas in flask $1$ is $m$,what is the mass of the gas in flask $2$?