Why is a hydrogen atom in one H2O molecule attracted to the oxygen atom in an adjacent H2O molecule?

• A. Because of London dispersion forces acting between the hydrogen and oxygen atoms.
• B. Because of hydrogen bonding, which occurs due to the attraction between the partially positive hydrogen atom and the partially negative oxygen atom of neighboring molecules.
• C. Because of covalent bonding forming between the hydrogen and oxygen atoms of separate molecules.
• D. Because of ionic bonding between the hydrogen and oxygen atoms of different molecules.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the nature of intermolecular forces, which are forces of attraction or repulsion between neighboring molecules, different from intramolecular forces like covalent bonds within a molecule.
2. Step 2: Recognize that in a water molecule (H\_2O), the oxygen atom is more electronegative than hydrogen atoms, causing the oxygen to have a partial negative charge (\delta-) and the hydrogens to have partial positive charges (\delta+).
3. Step 3: Identify that hydrogen bonding is a special type of dipole-dipole interaction that occurs when a hydrogen atom covalently bonded to a highly electronegative atom (like oxygen) is attracted to a lone pair of electrons on an electronegative atom in a neighboring molecule.
4. Step 4: Note that London dispersion forces are weak, temporary attractions due to momentary dipoles and are not the primary cause of attraction between water molecules; similarly, covalent and ionic bonds occur within or between ions, not between neutral water molecules.
5. Step 5: Conclude that the attraction between the hydrogen atom of one water molecule and the oxygen atom of another is due to hydrogen bonding, which arises from the electrostatic attraction between the partially positive hydrogen and the partially negative oxygen in adjacent molecules.