Boiling point is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid is influenced by several factors, including intermolecular forces, molecular weight, and atmospheric pressure.

H2O has a higher boiling point (100°C) than HF (20°C) because of the presence of stronger hydrogen bonding in H2O.

- Hydrogen bonding is a type of intermolecular force that occurs between molecules with a hydrogen atom bonded to a highly electronegative atom, such as oxygen or fluorine.

- In H2O, the oxygen atom is highly electronegative, which creates a strong partial positive charge on the hydrogen atoms. This allows the hydrogen atoms to form hydrogen bonds with the lone pairs of electrons on the oxygen atoms of neighboring water molecules.

- In contrast, HF has a weaker hydrogen bond because the electronegativity of fluorine is not as strong as that of oxygen. The hydrogen-fluorine bond is more covalent, and the partial positive charge on the hydrogen atom is smaller. This results in weaker hydrogen bonding between HF molecules.

The stronger hydrogen bonding in H2O leads to a higher boiling point because it requires more energy to break the hydrogen bonds and convert the liquid water into a vapor.