Why are the normal boiling points of #HF#, and #H_2O# so high?
Well, let's look at some figures first...........
If you look at a text, I would be surprised if you find a definitive, and comprehensive answer (certainly you will not get one from me!). Both molecules are small, and certainly in comparison to the homologous hydrides, these boiling points are high.
As far as I know, the best reason that I can advance is that the water can form 4 intermolecular bonds per molecule while