Hydrogen bond in water vapor [closed]








**Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers.
 
 






---








**Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/169915/edit).




Closed 9 months ago.








[Improve this question](/posts/169915/edit) 



As the temperature increases and liquid water changes to gas, are ALL the hydrogen bonds broken or they are just weaker?




Under commonly encountered conditions in industrial applications, essentially all hydrogen bonds are broken. Only at high pressures is hydrogen bonding likely to occur.


What happens is something of a Catch-22. If hydrogen bonding in water is significant, then it tends to form cross-linked structures because each molecule can both donate and accept two bonds, so the hydrogen bonding tends to form cross-linked structures that condense into a liquid. So to generate steam at near-atmospheric pressure you need enough thermal energy (temperature) to essentially break all the hydrogen bonds at once. Only at high pressure, where the gas becomes denser and more like a liquid, can hydrogen bonding become evident in the gas phase.


We may compare this with hydrogen fluoride, where chainlike structures form instead of cross-linked ones because each molecule donates and accepts only one hydrogen bond. The chainlike structures can be supported in the gas phase, so hydrogen fluoride gas can show hydrogen-bonded oligomers at relatively low pressures. See [here](https://chemistry.stackexchange.com/a/163076/17175).


 4