Question

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

Column 1	Column 2
Ion-ion	$\frac{1}{r}$
Dipole-dipole	$\frac{1}{r^3}$
London dispersion	$\frac{1}{r^6}$

Answer 1

Step 1: Ion-ion

1. The interaction energy between ions is represented by the formula $E=\frac{k{q}_1{q}_2}{r}$ where $E=Energy,q_1,q_2=ionsandr=distance$.
2. From the formula, it is clear that Ion-ion interaction energy is inversely proportional to the distance between ions i.e $E\propto \frac{1}{r}$.

Step 2: Dipole-dipole

1. The energy of the dipole-dipole interaction between polar molecules in solids is inversely proportional to $\frac{1}{r^3}$.
2. Dipole-dipole interaction energy$\propto \frac{1}{r^3}$

Step 3: London dispersion

1. London's dispersion forces only cover a tiny amount of ground. The distance to the power of six between two interacting particles is inversely proportional to the interaction energy.
2. London dispersion interaction energy$\propto \frac{1}{r^6}$

Hence, $A\to I,B\to II,C\to III$.