Question

Which statement best describes the intermolecular forces between H2 molecules and NH3 molecules in the liquid phase?

a) Hydrogen bonding between H2 and NH3 molecules.
b) Dipole-dipole interactions between H2 and NH3 molecules.
c) London dispersion forces between H2 and NH3 molecules.
d) Ion-dipole interactions between H2 and NH3 molecules.

Answer 1

The interaction between H2 and NH3 molecules in the liquid phase is best described as hydrogen bonding, with NH3 acting as a hydrogen bond donor and H2 as an induced hydrogen bond acceptor.

Step-by-step explanation:

The statement that best describes the intermolecular forces between H2 molecules and NH3 molecules in the liquid phase is hydrogen bonding between H2 and NH3 molecules. In NH3, nitrogen is highly electronegative and is covalently bonded to hydrogen, which creates a dipole.

The hydrogen atom of NH3 can act as a hydrogen bond donor, whereas H2, being a nonpolar molecule with no permanent dipole, cannot engage in hydrogen bonding by itself. However, when close to ammonia, the hydrogen of the ammonia molecule can induce a temporary dipole in the H2 molecule, allowing for some weak hydrogen bonding between H2 as hydrogen bond acceptor and NH3 as a donor.

This is nonetheless much weaker than typical hydrogen bonds because H2 isn't a traditional electronegative acceptor. However, the key types of intermolecular interactions are London dispersion forces, dipole-dipole interactions, and hydrogen bonds. As H2 is nonpolar, and NH3 can form hydrogen bonds, the best fit for their interaction is the weak hydrogen bonding that occurs due to the highly polarized nature of ammonia and the induced dipole in hydrogen.