Question

NH₃ has much higher boiling point than PH₃, because ______.

Options

• NH₃ has a much higher molecular mass.

• NH₃ forms hydrogen bonds.

• NH₃ contains ionic bonds while PH₃ contains covalent bonds.

• NH₃ undergoes umbrella inversion.

Answer 1

NH₃ has much higher boiling point than PH₃, because NH₃ forms hydrogen bonds.

Explanation:

Ammonia (NH₃) molecules can form intermolecular hydrogen bonds due to the high electronegativity difference between nitrogen and hydrogen, which makes the N-H bond polar. This hydrogen bonding causes NH₃ molecules to associate strongly, raising its boiling point. On the other hand, PH₃ molecules do not form hydrogen bonds; their intermolecular forces are only weak van der Waals forces, resulting in a much lower boiling point than NH₃.