For $1$ mol of a real gas kept at constant temperature $T$,the graph of $PV$ vs $P$ intersects the $PV$ axis at $20$. Hence,the temperature $T$ is ($R$ = universal gas constant).

When helium is allowed to expand into vacuum,a heating effect is observed. The reason for this is that

For a real gas at $25^{\circ} C$ temperature and high pressure $(99 \ bar)$,the value of the compressibility factor is $2$. The value of the Van der Waals constant '$b$' is $\times 10^{-2} \ L \ mol^{-1}$. (Nearest integer) (Given $R = 0.083 \ L \ bar \ K^{-1} \ mol^{-1}$)

At $S.T.P.$,if the compressibility factor $(Z)$ of a gas is less than $1$,then which of the following is true?

If the inversion temperature of a gas is $-80\,^{\circ}C$,then it will produce cooling under the Joule-Thomson effect at ............... $K$.

$A$ gas has a compressibility factor of $0.5$ and a molar volume of $0.4 \ dm^3 \ mol^{-1}$ at a temperature of $800 \ K$ and pressure $x \ atm$. If it shows ideal gas behaviour at the same temperature and pressure,the molar volume will be $y \ dm^3 \ mol^{-1}$. The value of $x / y$ is . . . . . .
[Use: Gas constant,$R = 8 \times 10^{-2} \ L \ atm \ K^{-1} \ mol^{-1}$ ]