Practice question · Multiple choice
Water boils at 100 °C while , a heavier molecule, boils at −60 °C. What explains the reversal?
Hints
- Ask what has to be overcome for a liquid to boil.
- Sulfur is far less electronegative than oxygen.
Show the answer
C. Hydrogen bonding, which S–H bonds cannot form
Why
Boiling point tracks intermolecular forces, not molecular mass. Hydrogen bonding is strong enough to invert the trend entirely, and is why water is liquid at all on Earth’s surface.
Practise Intermolecular interactions
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