Final answer:
Polar and nonpolar molecules do not mix to form a solution due to their different intermolecular forces. Heat may increase molecular motion but does not typically lead to a stable mixed solution. The solubility principle 'like dissolves like' encapsulates the behavior of mixing substances with similar intermolecular attractions.
Step-by-step explanation:
The reason polar molecules and nonpolar molecules typically do not mix to form a solution is due to the differences in intermolecular forces between them. Polar substances exhibit strong dipole-dipole interactions and possibly hydrogen bonding, while nonpolar substances are held together primarily by weaker London dispersion forces. These differences mean that the intermolecular attractions within the polar and nonpolar substances are stronger than what would exist between them, leading to immiscibility.
Even if heat is applied, these fundamental chemical interactions do not change. While heating can increase the kinetic energy of the molecules and may lead to a greater degree of mixing, it does not typically result in a stable solution. Only in some cases, and with sufficient heat, might it be possible to force some degree of miscibility. However, this is typically limited and may result in separation upon cooling.
Liquids that are miscible with each other, such as polar or hydrogen-bonding liquids, have intermolecular attractions (dipole-dipole or hydrogen bonding) that are strong enough to allow them to mix freely. In contrast, solubility between polar and nonpolar liquids is generally not achieved, which is described by the principle 'like dissolves like'.