Introduction:
Melting point is the temperature at which a substance changes from a solid to a liquid state. It can be used as a measure of the strength of the attractive forces between molecules. The higher the melting point, the stronger the forces of attraction between molecules.

Comparison of melting points:
The table below shows the melting points of different compounds:

| Compound | Melting Point (°C) |
|----------|:------------------:|
| Methane | -182 |
| Ethanol | -114 |
| Water | 0 |
| Sodium Chloride | 801 |
| Diamond | 3550 |

Analysis:
From the table, it can be observed that the force of attraction between the molecules is strongest in Sodium Chloride. This is because it has the highest melting point among the given compounds. The attractive forces between the sodium and chloride ions in the crystal lattice structure of sodium chloride are strong electrostatic forces of attraction. These forces are called ionic bonds, which are stronger than the covalent bonds present in other compounds.

Diamond has a very high melting point because its atoms are held together by strong covalent bonds, which require a lot of energy to break. However, the force of attraction between the molecules in diamond is not as strong as in sodium chloride because diamond is a covalent crystal, while sodium chloride is an ionic crystal.

Water has a melting point of 0°C because it is held together by weak hydrogen bonds between its molecules. These bonds are not as strong as ionic or covalent bonds and require less energy to break.

Ethanol has weaker intermolecular forces than water because it does not have hydrogen bonding. Methane has the weakest intermolecular forces because it is a non-polar molecule and has only weak London dispersion forces.

Conclusion:
In conclusion, the force of attraction between molecules is strongest in sodium chloride because it has the highest melting point among the given compounds. The strong electrostatic forces of attraction between the sodium and chloride ions in the crystal lattice structure of sodium chloride are responsible for this.