Question

Does ideal gas exist in reality?

Answer 1

Hint: We are asked to find out whether ideal gases exist in reality. We start by defining what ideal gas is. Then we move onto stating what makes a gas ideal. We can see if these conditions exist in the physical universe or not.
Formulas used: The ideal gas equation is as follows, $ PV = nRT $
Where $ P $ is the pressure of the gas
 $ V $ is the volume of the gas
 $ n $ is the amount of substance
 $ R $ is the universal gas constant
 $ T $ is the temperature.

Complete answer:
 An ideal gas is defined as all the collisions between the constituent molecules are completely elastic and there are no intermolecular attractive forces between the molecules.
For any gas to be ideal, it has to obey the following conditions,
1. The particles have negligible volume.
2. The molecules are of equal size and do not have any intermolecular forces, be it attractive or repulsive with other gases.
3. The particles move randomly but obey Newton's laws of motion.
4. The particles have perfectly elastic collisions and have no energy loss.
No gas in the physical universe can satisfy this condition. The closest gas to an ideal gas is hydrogen and helium.
In conclusion, ideal gas does not exist in reality and it is completely hypothetical.

Note:
Another way to define ideal gas is mathematically. Consider the equation, $ \dfrac{{PV}}{{nRT}} = 1 $
This factor is called the compression factor. For a gas to behave ideally, this factor has to be equal to one on computation. The greater the value of compression factor deviates from one, the greater it has a real nature.