Question

A real gas most closely approaches the behaviour of an ideal gas at
A) $\,15atm\,$ and $\,200K\,$
B) $\,1atm\,$ and $\,273K\,$
C) $\,0.5atm\,$ and $\,500K\,$
D) $\,15atm\,$ and $\,500K\,$

Answer 1

Hint: Kinetic theory of gases gives us the idea about ideal gas and real gas. Real gases deviate from ideal gases mainly because of assumptions in kinetic theory.

Complete step by step answer:
Let us first understand the assumptions in kinetic theory of gases about this;
Compared to the volume of the vessel, the volume of the gas particle is negligible while the volume of the individual gas particle is very significant.
There is no gaseous particle interaction while there are attracting forces between particles of real gas.
These are the main assumptions regarding the deviation of real gases from ideal gases.
Now, there is a law termed ideal gas law or ideal gas equation which states about the behaviour of ideal gases;
$\,PV = nRT\,$
Where, $\,P\,$ is the pressure of the gas
$\,V\,$ is the volume taken up by the gas
$\,T\,$ is the temperature of the gas
$\,R\,$ is the gas constant
$\,n\,$is the number of moles of the gas
If the gas pressure is too high, or the temperature is too low, substantial deviations from the ideal gas law can occur. So, a real gas obtains ideal gas behaviour at very low pressure and high temperature.
From the above explanations, it is clear that option C is the correct answer.


Note:
An ideal gas is a fictional gas which was conceived by scientists so that it would be far simpler to explain the basic Ideal Gas Law if factors such as intermolecular forces did not occur. Essentially, ideal gases are point masses that travel in continuous, spontaneous, straight-line motion. Its behaviour is defined in the Kinetic-Molecular Theory of Gases by the assumptions stated. This description of an ideal gas differs with the description of Non-Ideal Gas, since this equation illustrates how gas behaves.