Question

Why does ammonia has higher boiling point than phosphine?

Answer 1

Boiling point: The boiling point of a substance is the temperature at which the vapour pressure of a liquid equals the pressure surrounding and the liquid converts into a vapour.

• The boiling point of a liquid is affected by the surrounding atmospheric pressure.

Ammonia has a higher boiling point than phosphine is:

1. Ammonia has a greater boiling point than phosphine because ammonia has hydrogen bonding (due to covalent connections between hydrogen and nitrogen, which is more electronegative and has a lone pair).
2. Unlike phosphine, however, ammonia has hydrogen bonds due to the presence of a lone pair the covalent link between hydrogen and extremely electronegative nitrogen.
3. Ammonia has stronger intermolecular interactions and a higher boiling point because hydrogen bonds are stronger than London dispersion forces.