Hydrogen Fluoride and Water
 

It is said that Hydrogen bonding effects are especially pronounced in water because water has two hydrogen atoms and two unshared elctron
pairs ,giving each molecule the oppertunity to participate in four
hydrogen bonds.Sir,HF also has oppertunity to participate in four hydrogen bonds but even then it has much lower boiling point than water. HF also has lower melting point than water. Can you explain why? I'm first year college student. Thank you

Sincerely,
Vijay

In HF only Vanderwaal's forces are present where as in H2O both Vanderwaals as well as Hydrogen bonding, so to break the H-bonding it requires more amount of energy than taht of the Vanderwaals force.


Hope you got some idea from this :D

H-Bonding is much more powerful than Van der waals forces. As Opuntia said, the F element does not participate in H-bonding, so the ability to remain in the solid (or liquid) phase is greatly reduced. I hope this helps clear up any further questions on the matter.

HF v's H2O
 

Sorry folks, the fluorine DOES participate in H-bonding...

But in H2O there are two hydrogen atoms per molecule that can participate, whereas in HF there is only one. H2O has twice as much H bonding as HF and a consequently a higher bp.