Which type of intermolecular force is primarily responsible for the high boiling point of water (H_2O)?

• A. Ion-dipole forces
• B. Hydrogen bonding
• C. London dispersion forces
• D. Dipole-dipole interactions

Answer: (B)

Verified step by step guidance

1. Identify the molecular structure of water (H\_2O), noting that it is a polar molecule with a bent shape due to the two lone pairs on oxygen.
2. Recognize that water molecules have highly electronegative oxygen atoms bonded to hydrogen atoms, creating a significant dipole moment.
3. Understand that hydrogen bonding is a special type of dipole-dipole interaction that occurs when hydrogen is directly bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine.
4. Compare the types of intermolecular forces listed: ion-dipole forces occur between ions and polar molecules, London dispersion forces are weak forces present in all molecules, and dipole-dipole interactions are general attractions between polar molecules but weaker than hydrogen bonds.
5. Conclude that the unusually high boiling point of water is primarily due to hydrogen bonding, which is stronger than other dipole-dipole interactions and London dispersion forces.