$A$ certain amount of gas has a volume of $12 \, L$ at a pressure of $3 \, atm$. If the temperature remains constant,what pressure in $atm$ must be applied to reduce its volume to $9 \, L$?

An open glass tube is immersed in mercury such that a length of $8 \ cm$ extends above the mercury level. The open end of the tube is then closed and sealed,and the tube is raised vertically by an additional $46 \ cm$. What will be the length of the air column above the mercury in the tube now? (Atmospheric pressure = $76 \ cm$ of $Hg$)

When the temperature of a gas in a closed container is increased by $1 ^\circ C$,its pressure increases by $0.4 \%$. What is the initial temperature of the gas?

For one gram mole of a gas,the value of $R$ in the equation $PV = RT$ is nearly ...... $cal/K$

The pressure versus temperature graph of an ideal gas with an equal number of moles at different volumes is plotted as shown in the figure. Choose the correct alternative.

$A$ sample of $O_2$ gas has a volume of $100 \ ml$ at a pressure of $1 \ atm$ and a temperature of $27^{\circ}C$. If the pressure is increased to $2 \ atm$ while the volume remains $100 \ ml$,the new temperature will be .... $^{\circ}C$.