Question

Gases deviate from the ideal gas behavior because their molecules
A.Possess negligible volume
B.Have forces of attraction between them
C.Are polyatomic
D.Are not attracted to one another

Answer 1

Hint:We know the kinetic molecular theory of gases which are meant for ideal gas only. Some of the postulates are:-
The gas consists of a large number of minute particles called molecules. They have negligible volume.
There are no attractive forces between molecules. The molecules are completely independent of each other.
The pressure of the gas is due to the bombardment of molecules on the walls of the container.

Complete step by step answer:
The postulates of the kinetic theory of gas and it is applicable only for ideal gases.
For real gases,
In lower pressure and higher temperature, real gases show ideal gas behavior
But under high pressure and lower temperature, the total volume of gas will be decreased. But the volume of molecules will not change as it is incompressible. Therefore, molecules do not have a negligible volume
As the postulate says There are no attractive forces between molecules. This is valid only at lower pressure and high temperature because in these conditions molecules lie far from each other. But at lower temperature and high pressure, the volume of gas decreases(volume of the molecule is same) and molecules lie so close to each other. Thus, there are attractive forces.
Therefore, Gases deviate from the ideal gas behavior because their molecules
Have forces of attraction between them.

Thus, the correct option is B.

Note: Real gases obey the ideal gas equation, ${\text{PV = nRT}}$ at lower pressure and higher temperature. When the temperature is lower and pressure is higher, a large deviation from the ideal behavior is observed. These deviations are represented in terms of the Compressibility factor, Z.
${\text{Z = }}\dfrac{{{\text{PV(real)}}}}{{{\text{PV(ideal)}}}}$
When Z is equal to 1, it is ideal.