* Hydrocarbons: These molecules consist only of carbon and hydrogen atoms, forming long chains or ring structures. Examples include methane (CH4), ethane (C2H6), propane (C3H8), and benzene (C6H6).
* Oils and Fats: These are complex mixtures of lipids, primarily triglycerides. They are composed of long hydrocarbon chains with a glycerol backbone.
* Waxes: These are also lipids, but they have even longer hydrocarbon chains than oils and fats. They are typically solid at room temperature.
* Chlorine (Cl2): This is a diatomic molecule with a symmetrical structure, making it nonpolar.
* Carbon Dioxide (CO2): While it has polar bonds, the linear shape and symmetrical distribution of those bonds result in a nonpolar molecule.
Why are these molecules not soluble in water?
Water is a polar molecule, meaning it has a positive and negative end due to the uneven distribution of electrons. This allows water molecules to form hydrogen bonds with each other.
Nonpolar molecules, on the other hand, have an even distribution of electrons and do not form hydrogen bonds.
The "like dissolves like" rule applies: polar molecules dissolve in polar solvents, and nonpolar molecules dissolve in nonpolar solvents. Because water is polar and these molecules are nonpolar, they cannot form strong interactions and therefore are not soluble.
Note: There are exceptions to this rule. Some nonpolar molecules can have slight solubility in water due to weak Van der Waals forces. However, their solubility is significantly lower than polar molecules.
