Sciencemadness Discussion Board

Non-polar solvation

HydroCarbon - 20-3-2009 at 08:54

The simplistic mechanism for polar solvation is quite basic and easy to understand. The oppositely charged zones of the solvent and solute provide a means for the solvent to pull apart the solute and distribute it evenly throughout the medium.

A simplistic mechanism for non-polar solvation, however, puzzles me. I can't think of any reason why the individual units of solute would have a reason to be pulled into homogeneous solution by the solvent. Does true non-polar solvation even exist? Or does a slight polarity of so called non-polar molecules account for it's occurrence?

I tried searching Google for answers but came up with nada. I was hoping some of the bright folks here could help me out.

vulture - 21-3-2009 at 04:37

Entropy increase mostly, molecules in solution have vastly increased degrees of freedom.

watson.fawkes - 21-3-2009 at 09:06

Quote:
Originally posted by HydroCarbon
A simplistic mechanism for non-polar solvation, however, puzzles me. I can't think of any reason why the individual units of solute would have a reason to be pulled into homogeneous solution by the solvent.
The Wikipedia page on Solvation has a perfectly adequate explanation, but you've got to know some thermodynamics to make sense of it. The basic idea is that when attraction between solute and solution molecules is greater than solute and solute molecules, you get solvation. From that page: "The hydrogen bonding, ion-dipole, and dipole-dipole interactions occur only in polar solvents." These are three of the energy modes that cause the attraction to be different.

kmno4 - 22-3-2009 at 10:00

There is an excellent ebook:
Solvents and Solvent Effects in Organic Chemistry
http://www3.interscience.wiley.com/cgi-bin/bookhome/10762866...
Very interesting aspects of solvents and solvations, amazing acidities in gas phase and many other things.
Availble from anywhere (gigapedia etc.....)

[Edited on 22-3-2009 by kmno4]