GENERAL KNOWLEDGE

Detailed explanation-1: -Intermolecular forces (IMFs) can be used to predict relative boiling points. The stronger the IMFs, the lower the vapor pressure of the substance and the higher the boiling point.

Detailed explanation-2: -In general, molecules with weaker intermolecular forces will boil at lower temperatures.

Detailed explanation-3: -A small molecule like methane has very weak intermolecular forces, and has a low boiling point. However, as molecular weight increases, boiling point also goes up. That’s because the surface over which these forces can operate has increased. Therefore, dispersion forces increase with increasing molecular weight.

Detailed explanation-4: -Hydrogen bonding, dipole-dipole interactions, and ionic interactions represent the three intermolecular forces that have the greatest impact upon the boiling point. As the strength of these three intermolecular forces increases, the boiling point also raises.

Detailed explanation-5: -Compounds II and III only exhibit intermolecular London dispersion forces, so they would be the two lowest boiling compounds (weakest intermolecular forces).