What is the nature of container when talking about Boiling Point of a Liquid [ Vapour Pressure related ]? [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/167864/edit).




Closed last year.








[Improve this question](/posts/167864/edit) 



*From what I understand, whenever talking about calculating the value of Vapour Pressure we need to take a closed container as there needs to be an equilibrium established {R evaporation = R condensation} for us to be able to find it's value.*




---


My question is, whenever we talk about finding the boiling point of a liquid -


**Boiling point of a Liquid is the temperature at which the *Vapour Pressure of the Liquid becomes equal to the External / Atmospheric pressure*.**


So the container taken here need to be ***rigid*** or ***non-rigid*** ?


Both cases kinda made sense to me, but are equally confusing because I don't think both can be right at the same time.


Because if we take a non-rigid container so that the atmospheric pressure can be felt inside the container, but in real life examples we mostly deal with rigid containers.




Measuring of the equilibrium vapour pressure and measuring of the liquid boiling point are operations with very different settings.


Vapour pressure measurement is based on measuring of equilibrium pressure in a container, containing the liquid and pure liquid vapour at the given temperature.


Boiling is non-equilibrium process. Measuring of boiling point is done at constant pressure of open container.




---


Vapour pressure dependence on temperature can be measured alternatively as boiling point dependence on chosen external pressure.




---


Near the boiling point, there are being continuously created nano bubbles by random local processes (mostly local overheating), filled by saturated vapor. Hydrostatic pressure (external pressure included) of surrounding liquid is either high enough to make them disappear back to the liquid, either is too low, bubbles rapidly grow and leave the liquid.


The container is filled by vapour, that has the same pressure as is the external pressure.


 5