Chemistry - CHEMICAL BONDING Question with Solution | TestHub

It should be noted that if two dipoles are restricted to fixed orientations in a solid, the energy varies as $\frac{1}{{\mathrm{r}}^3}$ as shown earlier, and an energy expression containing that factor is frequently encountered. However, in a liquid the orientations change, and all orientations from the antiparallel attractive arrangement to the parallel repulsive arrangement are possible. There is some average orientation which is obtained by summing all of the possible orientations. When this is taken into account and the average orientation is used, the energy varies as $\frac{1}{r^6}$

• Net Vanderwaal forces also depends upon temperature.

•  H-Bond strength HF > H₂O > NH₃  

 Boiling point H₂O > HF > NH₃