Which of the following bond types is intermolecular?

Step 1: Analyze the question The question asks which bond type acts between molecules (intermolecular), not within them (intramolecular).

Step 2: Key concept

• Intramolecular (strong) bonds hold atoms together within a substance: • Covalent bond: sharing of electrons between atoms • Ionic bond: transfer of electrons, giving electrostatic attraction between ions • Metallic bond: attraction between positive metal ions and a "sea" of delocalised electrons
• Intermolecular (weak) forces act between separate molecules: • Van der Waals (London dispersion) forces • Dipole-dipole attractions • Hydrogen bonds

Step 3: Check each option

• A. Covalent bond: It holds atoms together inside a molecule (e.g., the O-H bonds inside a water molecule). It is intramolecular.
• B. Hydrogen bond: It forms between a hydrogen atom bonded to a highly electronegative atom (N, O, or F) in one molecule and a lone pair on N, O, or F in a neighbouring molecule. For example, it links one water molecule to another. It is intermolecular.
• C. Ionic bond: It holds ions together in a crystal lattice (e.g., NaCl). It is not intermolecular.
• D. Metallic bond: It holds atoms together in a metal. It is not intermolecular.

Step 4: Answer The hydrogen bond is the intermolecular one, which is option B.

Exam tip: Remember "N-O-F" for hydrogen bonding (H attached to N, O, or F). This is why water has a high boiling point compared with H₂S. Also, if a question says "between molecules", think of hydrogen bonds or van der Waals forces. Covalent, ionic, and metallic bonds are the "within" bonds.