Question

describe the relationship of attractive forces between molecules and the ability of a solvent to dissolve a substance

Answer 1

Welcome to OpenStudy. Isn't it, if the forces are stronger, it's harder for the molecule to separate and dissolve?

Answer 2

Molecules can be nonpolar or polar. The intermolecular interactions determine how well molecules can mix. Obviously, if two types of molecules can interact with each other, they will mix randomly and what we'll get is a solution. However, if they don't attract each other, they'll try to avoid the other and will form two separate layers - e.g. oil and water.

So, what causes it? It's Van der Waals forces. There are three types of them depending on the molecules. When two polar molecules come into contact, their electrostatic charges can repel or attract each other (same or opposite charges), which leads to molecules arranging one next to the other, so that positive charges are next to negative ones. They're sometimes called orientation forces.

If there is a polar and a nonpolar molecule nearby, the polar molecule can induce charges in the nonpolar one. The result is similar to the case above - we get an ordered series of molecules. Those interactions are known as inductive forces.

Finally, when two nonpolar molecules come in touch, they can, only temporary, after collision, induce dipole moment in each other. This leads to temporary attraction between them. They're also called dispersion forces.

Of the three above, the strongest forces are dipole/dipole interactions, followed by polar/nonpolar interactions and lastly, the weakest are the temporary forces induced between nonpolar molecules.


Further, solubility is affected by the formation of hydrogen bonds.