Do polar and nonpolar substances mix?

If that is the only attraction mechanism, no. Often molecules have polar ends to a longer chain non polar molecular chain, and in that case, yes.

Polar and nonpolar substances generally do not mix well together. This is because the intermolecular forces between polar molecules are different from those between nonpolar molecules.

To understand why they don't mix, let's first understand polarity. Molecules with polar covalent bonds have an uneven distribution of electron density, creating partial positive and partial negative charges. On the other hand, molecules with nonpolar covalent bonds have an even distribution of electron density, resulting in no significant partial charges.

In a mixture, the intermolecular forces (attractions between molecules) play a crucial role. Polar substances, like water (H2O), have strong intermolecular forces called hydrogen bonds. These forces occur when the positive end of one polar molecule is attracted to the negative end of another, forming a network of interactions. Nonpolar substances, such as oil or gasoline, have weak intermolecular forces, like London dispersion forces or van der Waals forces.

When you mix polar and nonpolar substances, the strong intermolecular forces of the polar molecules tend to stick together and avoid mixing with the weak intermolecular forces of the nonpolar molecules. This phenomenon is commonly known as "like dissolves like." In other words, substances with similar intermolecular forces tend to mix well, while substances with different forces tend to separate and form distinct layers.

However, there are exceptions to this general rule. Some polar and nonpolar substances can mix under certain conditions or with the help of emulsifiers or surfactants. Emulsifiers, like soap or detergent, have both polar and nonpolar parts, allowing them to connect with both types of molecules and create stable mixtures.

In summary, polar and nonpolar substances typically do not mix well due to their different intermolecular forces. Understanding the polarity of molecules helps explain why certain substances mix or remain separate when combined.