Which type of intermolecular force is predominant in liquid ammonia (NH_3)?

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

Answer: (D)

Verified step by step guidance

1. Identify the molecular structure of ammonia (NH_3). Ammonia consists of a nitrogen atom bonded to three hydrogen atoms, with a lone pair of electrons on nitrogen, making it a polar molecule.
2. Recall the types of intermolecular forces: London dispersion forces (present in all molecules), dipole-dipole interactions (between polar molecules), ion-dipole interactions (between ions and polar molecules), and hydrogen bonding (a special, strong type of dipole-dipole interaction involving H bonded to N, O, or F).
3. Determine if ammonia can participate in hydrogen bonding. Since NH_3 has hydrogen atoms bonded to nitrogen (a highly electronegative atom), it can form hydrogen bonds with neighboring NH_3 molecules.
4. Compare the strength of the intermolecular forces present. Hydrogen bonding is stronger than regular dipole-dipole interactions and London dispersion forces, so it will be the predominant force in liquid ammonia.
5. Conclude that the predominant intermolecular force in liquid ammonia is hydrogen bonding due to the presence of N-H bonds and the molecule's polarity.