Thread: Non-Polar Solvents and Solutes

I'm having a difficult time really understanding how a non-polar solute dissolves in a non-polar solvent.

My understanding of dissolution stems from how NaCl dissolves in water. The water molecules cause the Na+ ion and the Cl- ion to disassociate from one another because of the polar nature of water. Thus water dissolves NaCl.

When I try to apply this concept to a non-polar solvent and solute however, it doesn't work. If the solute and solvent are both non-polar, they really do not interact with each other at all except for intermolecular interactions. Where exactly is the dissolution?

Is my understanding of dissolution incorrect or incomplete, or is there something else I'm missing that is making it hard for me to understand the concept?

Dissolving a non-polar solute in a non-polar solvent is usually driven by entropy. The entropy of the system goes up if the solid dissolves into the liquid, so it does. Remember that dG=dH-TdS. With a salt dissolving in water, there's a major dH (enthalpy) component driving the process. With non-polar things, there's still the dS (entropy) component.