# How does the boiling point of water evolve with ambient pressure?

Sep 15, 2017

But first let's define $\text{boiling point}$. And it's a good definition to learn off by heart. The $\text{boiling point}$ is defined as 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 $\text{normal boiling point}$ occurs when the ambient pressure (and thus the vapour pressure of the boiling liquid) is ONE ATMOSPHERE. I would get this straight in your head first, because there is a lot going on here.
So we put the kettle on, and boil for a cup of tea. The water boils at $100$ ""^@C, and the vapour pressure of the steam is 1 atmosphere, and it pushes the atmosphere back..... If we have an involatile liquid, we can perform a vacuum distillation, and reduce the pressure to ${10}^{-} 3 - {10}^{-} 4 \cdot a t m$, we can substantially reduce the boiling point of the liquid.