Hydrogen bonding

• Water is polar because oxygen is very electronegative. However, the interacytion between molecules is much stronger than just dipole attractions because: oxygen atoms have lone pairs and the hydrogen has virtually lost its only electron to the very electronegative oxygen which causes the exposed hydrogen to have a very strong electric field.
• The exposed hydrogen has a strong electrostatic force of attraction from a lone pair of electrons from a neighbouring water molecule. The resulting hydrogen bond is much stronger than a dipole but much weaker than a covalent bond.
• Hydrogen acts as a bridge between two very electronegative atoms
• Hydrogen bonding only takes place between H+ with oxygen, fluorine, or nitrogen which have lone pairs
• There is a general increase in boiling point of hydrides as the groups are descended due to increasing size and hence id-id forces of the hydrides. The high values of N, O, and F are due to hydrogen bonding