The gas in a vessel is subjected to a pressure of $20 \ atm$ at a temperature of $27^{\circ}C$. If one-half of the gas is released from the vessel and the temperature of the remaining gas is raised by $50^{\circ}C$,the final pressure of the gas in the vessel is ....... $atm$.

The volume of a gas at $21^{\circ}C$ temperature and $768 \,mm$ pressure is $1 \,L$. If the density of the gas is $1.2 \,g/L$ at $NTP$,then its mass will be ..... $g$.

The molecular weight of a gas is $44$. The volume occupied by $2.2 \, g$ of this gas at $0^\circ C$ and $2 \, atm$ pressure will be ....... $lit$.

$A$ flask containing air at $27\,^{\circ}C$ at atmospheric pressure is corked up. $A$ pressure of $2.5\,atm$ would force the cork out. The temperature at which it happens is

$A$ long cylindrical pipe of radius $20 \,cm$ is closed at its upper end and has an airtight piston of negligible mass as shown. When a $50 \,kg$ mass is attached to the piston,it moves down. If the air in the enclosure is cooled from temperature $T$ to $T-\Delta T$,the piston moves back to its original position. Then $\Delta T / T$ is close to (Assuming air to be an ideal gas,$g=10 \,m/s^2$,atmospheric pressure is $10^5 \,Pa$)

When a gas filled in a closed vessel is heated by raising the temperature by $1^{\circ} C$,its pressure increases by $0.4 \%$. The initial temperature of the gas is ..........$K$.