[Ter]

Why does HF have very high boiling point, unlike HI, HCl, HBr?
A.) The electronegativity of fluorine is much higher than for other elements
B.) THere is hydrogen bonding between HF molecules.

I thought both options were correct, which will take precedence over the other and why?

Thank you so much!

[Tittywahah]

Have you tried google?

Hydrogen bonding, probably. Fluorine has a high amount of electron density and this pulls away the electrons bonding the Hydrogen atom. The nucleus of the Hydrogen is exposed and since it is just a proton, it has a positive charge. This makes HF polar and it acts like a magnet. The Hydrogen atom on one molecule is attracted to the Fluorine atom on another molecule. The attraction forms an unstable bond. The bond is weaker than a molecular bond, but there are many of them and they influence the properties. HF boils at a higher temperature because the hydrogen bonds are holding the molecules together. The same thing happens with water. All other Hydrides , e.g. H2S, NH3 and CH4, are
gasses around 70F while water is liquid. This is because of the hydrogen bonding. Hydrogen bonding is also what holds DNA strands together and gives enzymes their shape.
SOURCE:  http://answers.yahoo.com/question/index?qid=20091104115550AA6aTua
OR
http://wiki.answers.com/Q/Why_does_hydrogen_flouride_have_a_higher_boiling_point_than_hydrogen_chloride

And:   http://wiki.answers.com/Q/Why_is_fluorine_the_most_electronegative_element

[Ter]

Thank you!

[Tittywahah]

Thank you!

You're welcome