I think air is a solution because it is made up of different types of gases including 21 percent oxygen, 78 percent nitrogen, and one percent trace gases.
Salt dissolves in water
The solution has already reached its solubility and cannot dissolve any more solute
A dilute solution has a little bit of solute dissolved in the solvent, while a concentrated solution has a large amount of solute dissolved in the solvent
If you heat a solution normally the solubility increases meaning more solute can be dissolved in the solvent
i hope i was able to help :)
