What type of intermolecular force is predominantly responsible for the unusually high boiling point of water relative to other group 16 hydrides (such as )?

Answer and explanation

Correct answer: C. Hydrogen bonding

  1. Step 1: Analyze molecular structure of water: Highly electronegative oxygen bonded to small hydrogen atoms creates strong molecular dipoles.
  2. Step 2: Identify specific intermolecular interaction: Strong electrostatic attraction between hydrogen and lone pairs on oxygen of adjacent molecules constitutes hydrogen bonding.
  3. Step 3: Explain anomaly: Hydrogen bonding requires substantial thermal energy to break, creating an abnormally high boiling point () compared to ().
Answer
Hydrogen bonding.
Why not the others: 'London dispersion forces' are present in all molecules but are weak in small molecules like water; 'Dipole-dipole attractions' exist but are significantly weaker than hydrogen bonds; 'Covalent network bonding' is an intramolecular solid lattice (e.g., diamond, quartz).

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