Question

How is saturated air different from unsaturated air?

Answer 1

First we need to figure out what is saturated and unsaturated air. Then we need to figure out their properties and determine the difference between them. The main difference lies in their definition.

Complete answer:
Saturated air is the air that contains or holds the maximum capacity of water vapour in it. The amount or maximum limit of water vapour that a given quantity of air can hold is called saturated vapour. The relative humidity of saturated air is considered to be $100\%$ while that of unsaturated air is much less than $100\%$ .
Unsaturated air is the opposite of saturated air, it contains less amount of water vapour, i.e. it can hold more water vapours.
Both forms of air can be interchanged by altering the temperature. Saturated air can be made unsaturated by increasing the temperature. Similarly cooling the unsaturated air will form saturated air. Mixing two volumes of unsaturated air will also form the saturated air.
Hence, we can conclude that the main difference between saturated and unsaturated air is the extent of relative humidity or the amount of water vapour it holds.

Note:
At the saturated condition, the saturation vapour pressure becomes comparable to the actual pressure of the vapour in the air at that particular temperature. It is created in a confined place. This phenomenon is similar to the saturated solution of the sugar solution or any homogeneous mixture. For comparison in the solution, the solvent is water and here the restricted spatial space is solvent and solution for the solution is sugar and here the steam is solute.