Question
Out of NH3 and PH3, which has higher boiling point and why?
Solution
The boiling point of NH3 is higher than that of PH3. The nitrogen atom is more electronegative (3·0) than phosphorus (2·1). As a result, NH3 exhibits intermolecular hydrogen bonding while PH3 does not show any hydrogen bonding. Thus, extra energy is needed to break these hydrogen bonds in NH3. Thus, NH3 has higher boiling point than PH3.
