Match the type of interaction in column A with the distance dependence of their interaction energy in column B: 

(I)Ion-Ion	(a) ${\mathrm{r}}^{-1}$
(II) dipole - dipole	(b) ${\mathrm{r}}^{-2}$
(III) London dispersion	(c) ${\mathrm{r}}^{-3}$   (d) ${\mathrm{r}}^{-6}$

 

Type of interaction is directly proportional to interaction energy

 The interaction energy between ion-ion

ions are given by the equation $\mathrm{E}=\frac{{\mathrm{kq}}_1{\mathrm{q}}_2}{\mathrm{r}}$. where E=energy, ${\mathrm{q}}_1,{\mathrm{q}}_2$=ion, r=distance.

From this equation it is clear that the ion-ion interaction energy is inversely proportional to the distance between the ions. 

Dipole-dipole

The energy of the dipole-dipole interaction between polar molecules in solids is inversely proportional to ${\mathrm{r}}^3$.

 London Dispersion

The London dispersion force covers only a small portion of the ground. The sixth power distance between two interacting particles is inversely proportional to the interaction energy.

Therefore

Ion-Ion =${\mathrm{r}}^{-1}$

Dipole-dipole=${\mathrm{r}}^{-3}$

London dispersion=${\mathrm{r}}^{-6}$

So, the correct option is D.