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

• A. London dispersion forces
• B. Hydrogen bonding
• C. Dipole-dipole interactions
• D. Ion-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 hydrogen atoms directly bonded to a highly electronegative atom (oxygen), which is a key condition for hydrogen bonding.
3. Understand that hydrogen bonding is a special type of dipole-dipole interaction that occurs when hydrogen is bonded to N, O, or F, leading to stronger intermolecular attractions than regular dipole-dipole forces.
4. Compare the strength of different intermolecular forces: London dispersion forces are weakest, dipole-dipole interactions are moderate, and hydrogen bonding is stronger, which explains water's unusually high boiling point.
5. Conclude that the primary intermolecular force responsible for water's high boiling point is hydrogen bonding, due to the strong attraction between the hydrogen atoms of one molecule and the oxygen atoms of another.