# Why do boiling points differ between materials?

Jan 8, 2018

Let us take 2 common liquids: $\text{(i) water; and (ii) diethyl ether....}$
At $34.6$ ""^@C, water has a vapour pressure of $41.1 \cdot m m \cdot H g$...but at this temperature, diethyl ether has a vapour pressure of $760 \cdot m m \cdot H g$. How did I know the latter? Because I know that at the $\text{normal boiling point}$, the vapour pressure of the liquid is $1 \cdot a t m \equiv 760 \cdot m m \cdot H g$. (How did I know the former? Well, I have got a handy table in front of me that tells me the vapour pressure of water at various temperatures.)
So a question for you to consider, what is the vapour pressure of water at $100$ ""^@C?