Question

Polar molecules exhibit dipole-dipole forces. Do they also exhibit dispersion forces? Explain.

Short answer

Yes, polar molecules can exhibit dipole-dipole forces as well as the dispersion forces which are the weak force as it comes into play due to the effect of induction in polar and non-polar molecules.

Step-by-step solution

Intermolecular Forces

Intermolecular forces are the interaction which are formed by the attraction of the two having opposite charges (partial positive and partial negative charge). The opposite charge are formed by the presence of the electron-negative atom in the molecule. Due to the presence of an electron-negative atom, there is and induced partial positive charge is generated on the electron-positive charge (or less electron-negative charge) atom. There will be an attraction between the both oppositely charges to form a bond.

Dipole-dipole Interaction: These interactions are the attractive forces which present in the polar molecules.Polar molecules have permanent dipoleswhich are produced by the presence of the opposite charge of the atom.

London dispersion interaction: It is the weak bond which is formed for the short period of time. The bond is formed between the polar and non-polar molecules due to the phenomena of induction.

Interaction Explanation

Polar molecules are those molecules which have a permanent dipole moment. These kind of molecules can show dipole-dipole interaction. The polar molecule can also show London dispersion which can also be called dipole-induced dipole interaction. London forces follow the principle of induction as the polar molecule induces some polarity in the non-polar molecule. Due to the induced polarity in the non-polar molecule, it shows interaction for short period of time and forms a weaker bond.