# What would happen to the boiling point of a substance if the elevation were to rise?

Jul 14, 2017

The boiling point of the substance would reduce.......

#### Explanation:

By definition, the boiling point of a liquid is the temperature at which the vapour pressure of the liquid is equal to the ambient pressure, and bubbles of vapour form directly in the liquid. The $\text{normal boiling point}$ is specified when the ambient pressure is $1 \cdot a t m$, and thus the vapour pressure of the liquid is $1 \cdot a t m$ at its boiling point.

I do acknowledge that this definition is wordy, and it is the level of knowledge expected of a 1st year undergraduate chemist........ But this principle underlies vacuum distillation, where we can boil an otherwise involatile liquid by reducing the ambient pressure (by applying a vacuum) and reducing the temperature at which the vapour pressure of the liquid is equal to the ambient pressure.

The highest altitude city to which I have been was Denver, Colorado, approx. 1500 m above sea level. The boiling point of water is approx. $95$ ""^@C here. What would you surmise with regard to atmospheric pressure in Denver? The boiling point of water on top of Mount Everest is apparently $72$ ""^@C (almost cold enuff to bath in-not that I would want to have bath on a snow-capped mountain). Are these facts consistent with what we have argued?