Which of the following best explains why water (H_2O) has a much higher boiling point than would otherwise be predicted?

• A. Water molecules are held together by ionic bonds.
• B. Water molecules form strong hydrogen bonds with each other.
• C. Water molecules have a high molar mass compared to similar compounds.
• D. Water molecules experience only London dispersion forces.

Answer: (B)

Verified step by step guidance

1. Identify the types of intermolecular forces present in water (H\_2O). Water molecules are polar and can form hydrogen bonds due to the presence of highly electronegative oxygen atoms bonded to hydrogen.
2. Understand that hydrogen bonding is a special, strong type of dipole-dipole interaction that occurs when hydrogen is bonded to N, O, or F, leading to stronger attractions between molecules compared to other intermolecular forces.
3. Compare hydrogen bonding to other intermolecular forces such as London dispersion forces and dipole-dipole interactions, noting that hydrogen bonds are significantly stronger and require more energy (higher temperature) to break.
4. Recognize that water does not have ionic bonds between molecules; ionic bonds occur between ions, not neutral molecules like water.
5. Conclude that the unusually high boiling point of water is due to the strong hydrogen bonds between water molecules, which require more heat energy to overcome during the phase change from liquid to gas.