Correct Answer - Option 3 : Strongest hydrogen bonding
Concept:
Due to the strong H-bonding between HF molecules. HF has highest boiling point among the hydrogen halides.
Because of hydrogen bonding, Fluorine is the most electronegative element so the electrons shared in the HF covalent bond spend more time around the F atom. Thus, there is a larger dipole in HF so there are larger electrostatic forces to be overcome in boiling HF. Therefore, more energy is required to break the intermolecular forces in HF than the other hydrogen halides and so it has a higher boiling point.
Hydrogen bonds are strong intermolecular forces created when a hydrogen atom bonded to an electronegative atom approaches a nearby electronegative atom. The hydrogen bond is one of the strongest intermolecular attractions, but weaker than a covalent or an ionic bond.
The HF has the highest boiling point among the hydrogen halides because it has strongest hydrogen bonding.
