Hydrogen bonding

Definition

Hydrogen bonding is a strong type of dipole-dipole interaction that occurs between molecules when hydrogen is covalently bonded to electronegative atoms like oxygen, nitrogen, or fluorine. This bond results in higher boiling and melting points for substances.

5 Must Know Facts For Your Next Test

1. Hydrogen bonds are significantly stronger than van der Waals forces but weaker than covalent and ionic bonds.
2. The presence of hydrogen bonding increases the boiling point and melting point of compounds.
3. Water's unique properties, such as high surface tension and capillary action, are due to hydrogen bonding.
4. In DNA, hydrogen bonds between complementary base pairs hold the double helix structure together.
5. Ethanol ($C_2H_5OH$) and water are examples of substances that exhibit hydrogen bonding.

Review Questions

• What atoms must be present for hydrogen bonding to occur in a molecule?
• How does hydrogen bonding affect the boiling point of a substance?
• Why is water's surface tension higher compared to other liquids?

Related terms

Dipole-Dipole Interaction: An intermolecular force occurring between polar molecules due to the attraction between partial positive and partial negative charges.

Van der Waals Forces: Weak attractions between molecules or parts of molecules resulting from transient local partial charges.

Electronegativity:

A measure of an atom's ability to attract shared electrons towards itself in a chemical bond.