In liquid the particles are a little far away from each other but they have a powerful attractive force in between them by which we can separate them into layers of density
On the other hand in gas the particles are too far apart from each other so we can't separate them into layers of density.
Hey there! I'll try to provide you with my best answer.
Answer: The main reason why it probably wouldn't be seperated is because the molecules in gas are much farther away from each other. This created a huge gap within the two states so sometimes it's likely to be not seperated. But it solely depends on the sort of gas is being used. If they have higher density difference then it is possible to be seperated.
If air is included as gas then yes, because there is heavy and light air. The heavy air is the cold air which you feel at night. Meanwhile the light air the warm air which rises in the sky during day light. Both of them are seperated because of their densities. Or atleast they are seperated into layers themselves. For example: this slightly cold and hot air is felt when your nearby a camp fire.
