Question: Graphs showing the behaviour of several different gases follow. Which of these gases exhibit behaviour significantly different from that expected for ideal gases?

One of the four fundamental states of matter, a gas is made up of particles with no definite volume or structure.

The equation for the ideal gas is:

\({\rm{PV = nRT}}\)

Gas A: At constant \({\rm{n,P,V \alpha T}}\), according to the ideal gas equation. The \({\rm{V}}\) vs \({\rm{T}}\) graph displays a straight line that increases linearly with volume and temperature, indicating that Gas A behaves ideally.

Gas B: At constant\({\rm{ n,PV = }}\) constant, according to the ideal gas equation. As \({\rm{PV}}\) does not rely on \({\rm{P}}\), the plot of \({\rm{PV}}\) v/s \({\rm{P}}\) should remain constant as pressure increases, as illustrated in the graph. As a result, Gas B behaves ideally.

Gas C: \({\rm{Z = (}}\frac{{{\rm{PVm}}}}{{{\rm{RT}}}}{\rm{)}}\) for gas C when this ratio is equal to one, ideal gas behaviour is indicated. With rising \({\rm{PV/RT}}\), \({\rm{Z}}\) should remain constant for an ideal gas. The graph of Gas C, on the other hand, reveals a major departure from the ideal gas behaviour.

Gas D: \({\rm{Z = (}}\frac{{{\rm{PVm}}}}{{{\rm{RT}}}}{\rm{)}}\) for Gas D when this ratio is equal to one, ideal gas behaviour is indicated. For an ideal gas, \({\rm{Z}}\) should remain constant as \({\rm{PV/RT}}\) increases while \({\rm{n,P}}\) remains constant. The graph depicts Gas D's optimal behaviour.

Gas E: At constant \({\rm{n,P,V \alpha T}}\), according to the ideal gas equation. The \({\rm{V}}\) vs \({\rm{T}}\) graph should show a straight line that increases linearly as volume and temperature increase. The graph of Gas E, on the other hand, indicates a non-linear growth. As a result, Gas E deviates significantly from the ideal gas behaviour.

Gas F: At constant \({\rm{n,P,V \alpha T}}\), according to the ideal gas equation. The graph of \({\rm{P}}\) vs. \({\rm{T}}\) should show a straight line that increases linearly with pressure and temperature. The graph of Gas F, on the other hand, indicates a non-linear growth. As a result, Gas F deviates significantly from the ideal gas behaviour.

Therefore, the gas C, E and F are different from the ideal gas.