Which type of intermolecular force is the strongest present in liquid ammonia (NH_3)?

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

Answer: (A)

Verified step by step guidance

1. Identify the molecular structure of ammonia (NH_3). Ammonia is a polar molecule with a nitrogen atom bonded to three hydrogen atoms and a lone pair on nitrogen.
2. Recall the types of intermolecular forces: London dispersion forces (present in all molecules), dipole-dipole interactions (present in polar molecules), hydrogen bonding (a special, stronger type of dipole-dipole interaction involving H bonded to N, O, or F), and ion-dipole forces (involving ions and polar molecules).
3. Determine which intermolecular forces ammonia can exhibit. Since NH_3 is polar, it has dipole-dipole interactions and London dispersion forces. Because it has hydrogen atoms bonded to nitrogen (a highly electronegative atom), it can form hydrogen bonds.
4. Compare the strengths of these forces. Hydrogen bonding is generally stronger than dipole-dipole interactions and London dispersion forces, and ion-dipole forces require ions, which are not present in pure liquid ammonia.
5. Conclude that the strongest intermolecular force present in liquid ammonia is hydrogen bonding due to the N-H bonds and the lone pair on nitrogen enabling strong intermolecular attractions.