The short general principle of solubility states that “like dissolves like.” This principle means that substances with similar chemical properties and polarities tend to dissolve in each other.
To elaborate, polar substances (those with a significant difference in electronegativity between atoms leading to partial charges) will dissolve well in other polar substances. For instance, salt (which is ionic and polar) dissolves readily in water (which is also polar).
On the other hand, non-polar substances (those that do not have significant charges) will not dissolve in polar solvents. Instead, they dissolve well in other non-polar substances. An example of this can be seen when oil (non-polar) does not mix with water (polar), but it will dissolve in other non-polar substances like hexane.
Overall, understanding this principle helps in predicting how different substances will behave when mixed, which is particularly important in many fields, including chemistry, biology, and environmental science.