Which of the following laws is followed by a hot air balloon used for sports and meteorology?

An ideal gas is heated in a rigid container so its temperature rises. Which is incorrect for this process?

When $2 \ g$ of a gaseous substance $A$ is introduced into an initially evacuated flask at $25^{\circ} C$,the pressure is found to be $1 \ atm$. $3 \ g$ of another gaseous substance $B$ is added to it at the same temperature and pressure. The final pressure is found to be $1.5 \ atm$. Assuming ideal gas behaviour,the ratio of molar masses of $A$ and $B$ is:

The volume of a gas is $4 \ dm^3$ at $0^{\circ} C$. Calculate the new volume at constant pressure when the temperature is increased by $10^{\circ} C$. (in $dm^3$)

The same gas is filled in two containers $X$ and $Y$. If the pressure,volume,and absolute temperature of the gas in container $X$ are three times those in container $Y$,and the mass of the gas in $X$ is $m \, g$,what will be the mass of the gas in $Y$?

$400 \ cm^{3}$ of oxygen at $27\,^{\circ}C$ were cooled to $-3\,^{\circ}C$ without change in pressure. The contraction in volume will be ............... $cm^{3}$