Boiling point of H2O >HF > NH3
 

How do you explain the boiling point of H2O > HF > NH3 ?
We know that their boiling point is very high due to the hydrogen bond but considering the electronegativity of O, N, F. Florine is more electronegativity than oxygen and yet the boiling point of H2O is higher than HF, why??

In H2O there's hydrogen bonding between the molecules.

H bonding
 

In water there are twice as many H-bonds 'cos there are two H atoms per molecule. This allows water to form a diamond type lattice with extensive hydrogen bonding throughout. This cannot happen with HF

take a look at this

Re: Boiling point of H2O >HF > NH3
 

[b]Notice that each water molecule can potentially form four hydrogen bonds with surrounding water molecules. There are exactly the right numbers of + hydrogens and lone pairs so that every one of them can be involved in hydrogen bonding.

This is why the boiling point of water is higher than that of ammonia or hydrogen fluoride. In the case of ammonia, the amount of hydrogen bonding is limited by the fact that each nitrogen only has one lone pair. In a group of ammonia molecules, there aren't enough lone pairs to go around to satisfy all the hydrogens.

In hydrogen fluoride, the problem is a shortage of hydrogens. In water, there are exactly the right number of each. Water could be considered as the "perfect" hydrogen bonded system.

http://www.chemguide.co.uk/atoms/bonding/hbond.html