# How to compare the boiling point of water, ammonia and hydrogen fluoride?

According to the values of boiling points that I found on internet the order is as follows:

$\ce{H2O}$ > $\ce{HF}$ > $\ce{NH3}$

I was expecting $\ce{HF}$ to have highest boiling point because F is the most electronegative atom hence should form stronger H Bonds.

Now, I think the factor here might be number of H Bond rather than strength of H Bond.

• $\ce{H2O}$ have 2 lone pair and 2 H atoms, hence it can form 4 H Bonds with surrounding molecules.

• Similarly $\ce{NH3}$ is also capable of forming 4 H Bonds with surrounding molecules.

• $\ce{HF}$ on the other hand is only capable of forming 2 H Bonds with surrounding molecules.

Still the above hypothesis doesn’t explain why the boiling point of $\ce{HF}$ is greater than $\ce{NH3}$. I’m not sure what am I missing here.

And the difference in electronegativity is higher in $\ce{HF}$ than in $\ce{NH3}$.
Hence boiling point order is $\ce{H2O} > \ce{HF} > \ce{NH3}$