Which substance has the highest boiling point?

[tica86]

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??

 

[Borek]

What does boiling point depend on?

 

[tica86]

intermolecular bonds

 

[Borek]

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?

 

[ciderc]

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?