Concept:The strength of a single hydrogen bond is determined by the difference in electronegativity between the hydrogen atom and the atom it is bonded to.
Formula:$$ \text{H-Bond Strength} \propto \Delta \text{E.N.} $$
Solution:- Fluorine is the most electronegative element (E.N. = 4.0).
- The massive electronegativity difference in HF causes the hydrogen atom to become extremely electron-deficient (highly positive).
- This highly positive hydrogen creates the strongest singular intermolecular electrostatic attraction (H-bond) observed in simple molecules.
- Note: While water has a higher boiling point due to forming more H-bonds per molecule, the individual bond strength is highest in HF.
Why other options are incorrect:Oxygen (3.5) and Nitrogen (3.0) are less electronegative than Fluorine. Hydrogen Sulfide (\( \text{H}_2\text{S} \)) practically does not form hydrogen bonds due to sulfur's larger size and lower electronegativity.
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