Which substance has the highest boiling point?

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SUMMARY

The substance with the highest boiling point among H2O, CO2, CH4, Kr, and NH3 is H2O (water). This is primarily due to the strong hydrogen bonding present in water, which is a result of oxygen's higher electronegativity compared to nitrogen in NH3. While both water and ammonia can form four hydrogen bonds, the stronger hydrogen bonds in water lead to a higher boiling point. The discussion emphasizes the importance of intermolecular forces, particularly hydrogen bonding, in determining boiling points.

PREREQUISITES
  • Understanding of intermolecular forces, specifically hydrogen bonding
  • Knowledge of electronegativity and its effects on molecular interactions
  • Familiarity with molecular structures of H2O, NH3, CO2, CH4, and Kr
  • Basic principles of boiling point determination in substances
NEXT STEPS
  • Research the concept of hydrogen bonding in detail
  • Study the electronegativity values of common elements
  • Explore the differences between various types of intermolecular forces
  • Learn about boiling point trends in different molecular compounds
USEFUL FOR

Chemistry students, educators, and anyone interested in understanding the factors influencing boiling points and molecular interactions.

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Of the following substances which has the highest boiling point?

H20, CO2, CH4, Kr, NH3

I already know the answer is H20 but I would've initially chosen NH3 because of the nitrogen bond to hydrogen but that's obviously wrong. Is it H20 because oxygen is more electronegative then nitrogen??
 
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What does boiling point depend on?
 
intermolecular bonds
 
More like forces (van der Waals forces are not classified as bonds). OK, what kinds of intermolecular forces & bonds will be at work in each molecule? Which of these are the strongest?
 
The hydrogen bonding between molecules in this case is the strongest.
Oxygen being more electronegative than nitrogen will form stronger hydrogen bonds.
Also water there are 2 lone pairs of electrons whereas the nitrogen in NH3 has only 1 lone pair of electrons.But ,correct me if I am wrong , in water, there are 4 possible hydrogen bonds (2 from oxygen and 2 from hydrogen) and in ammonia there are also 4 possible hydrogen bonds (1 from nitrogen and 3 from hydrogen).
So the only difference is then the electronegativity of oxygen which determines the boiling point?
 

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