Ideal gas does not show Joule-Thomson effect.

The conditions for triple point of H₂O.

the particular temperature and pressure at which the solid, liquid, and gaseous phases of a given substance are all at equilibrium with one another.

Hint: In the case of Ideal gas, the force of attraction between molecules is zero.

Ideal gas molecules are separated from each other by large space and the actual volume of the gas molecule is negligible with respect to the volume of gas. Due to large intermolecular spaces, there is no force of attraction between the ideal gas molecules and they are completely independent of each other.

Hint: Gas having a high force of attraction liquify easily

SO₂ has a higher value of van der Waals' forces of attraction and thus, is more easily liquefied.

value of  'a" for

SO₂ has higher value of "a" hence it has maximum forces of attraction, thus, it will liquify easily.

Hint- a is measure of intermolecular strength and b depends upon molecular weight

EXPLANATION 

Higher the polarity, easier to liquify.

The ease of liquification of a gas depends on their intermolecular force of attraction which in turn is measured in terms of van der Waals’ constant ‘a’.

Hence, higher the value of ‘a’, greater the intermolecular force of attraction, easier the liquification.

In the present case, NH₃ has highest ‘a’, can most easily be liquefied.Molecular weight of nitrogen is greater than ammonia ,SO the value of b for nitrogen

Hint: Easily liquefiable gases exhibit maximum deviation

Easily liquefiable gases like NH₃, SO₂ etc. exhibit maximum deviation from ideal gas as for them Z<<< 1 .

CH₄  also exhibits deviation but it is less as compared to NH₃.

Joule-Thomson effect occurs at constant enthalpy.

In the case of gases, the viscous resistance arises from the transport of molecules from one layer to another, with transfer of momenta, so that the fast moving molecules in one layer are slowed down, while the slow moving molecules in the other are accelerated. This momentum transfer increases with increase in temperature. A simple expression for the viscosity of a gas

The critical volume is three times the Van der Waals constant 'b'.