What is an unsaturated gas?

Answer 1

Saturated air is air that is holding as much moisture as it can at a given temperature. Unsaturated air does not contain the full amount of moisture possible at a given temperature.

Answer 2

The word saturated could have several meanings. The common usage of the word saturated would mean "holding as much of a liquid as possible". For example, if you spend an hour in the pouring rain your jacket would be saturated.

Another usage, more chemically relevant, is "having as many particles present in solution as possible". Take sugar water as an example. If you pour some sugar in a glass of water it will dissolve. However, you couldn't add sugar to the glass of water forever and have it still dissolve. There is a point after which any added sugar will not be able to dissolve. When that occurs we say that the solution is saturated.

A final meaning of the word saturated has to do with organic molecules. Carbon atoms are most stable when they form 4 bonds, so most of the time that's how you'll find them. A saturated organic molecule has as many carbon-hydrogen bonds as possible, meaning there are no carbon-carbon double or triple bonds in the molecule. This is where the idea of saturated and unsaturated fats come from. A saturated fat is a fat that has no double bonds in it's carbon chain. An unsaturated fat has at least one double bond. This carbon-carbon bond means that there are fewer hydrogen atoms in the molecule. You can even count "degrees of unsaturation". A molecule with two degrees of unsaturation has two double bonds. So, a saturated gas would be a gas comprised of organic molecules that don't have any carbon-carbon double bonds.

Answer 3

when the humidity content in air is less than the maximum it can retain at a particular temperature and pressure condition, air is said to be unsaturated.