Question

Explain which of the following molecular substances would exhibit the greatest degree of hydrogen bonding in the liquid phase: BH3, CH, H2, NH3, HS. Would hydrogen bonding be an important intermolecular interaction for these substances in the gas phase?

Answer 1

Out of the listed molecular substances, only NH₃ exhibit hydrogen bonding, because it only satisfeis all the condition for hydrogen bonding.

Condition for hydrogen bonding-

• atleast one hydrogen atom is directly bonded to a highly electronegative atom
• The electronegative atom must be small

Only N, O, F satisfies above mentioned conditions, hence are able to form hydrogen bonding.

In gaseous phase the molecular spacing becomes so high and the molecular dynamics becomes so random that, it would not be an important intermolecular interaction in gas phase.