Question #bd419

1 Answer
Dec 16, 2016

The major intermolecular forces between propanoic acid and heptane are dipole-induced dipole forces.


The formula of propanoic acid is


It has a highly polar #"OH"# group.

The formula of heptane is


It is a nonpolar hydrocarbon, so its strongest intermolecular forces are London dispersion forces.

When the two liquids are mixed, the strong #"OH"# dipole in the propanoic acid molecule can deform the electronic cloud of the heptane.

It induces a dipole in the heptane molecule, so the interaction is called a dipole-induced dipole force.

You would expect propanoic acid to be "insoluble" in heptane, but the dipole-induced dipole forces increase the solubility to about 6 g/100 g heptane.