Options :

1. For an ideal gas, the enthalpy is independent of pressure.

2. For a real gas going through an adiabatic reversible process, the process equation is given by 𝑃𝑉^𝛾 = constant, where P is the pressure, V is the volume and 𝛾 is the ratio of the specific heats of the gas at constant pressure and constant volume.

3. For an ideal gas undergoing a reversible polytropic process 𝑃𝑉 ^1.5 = constant, the equation connecting the pressure, volume and temperature of the gas at any point along the process is 𝑃 / 𝑅 = 𝑚𝑇/ 𝑉 , where 𝑅 is the gas constant and 𝑚 is the mass of the gas

4. Any real gas behaves as an ideal gas at sufficiently low pressure or sufficiently high temperature.