Question

give Reason for the higher point of h2O than that of HF and NH3​

Answer 1

Answer

The boiling point of H₂O is higher than that of HF because

• The number of hydrogen bonds formed per H₂O molecules are almost twice then those per HF molecule.
• In vapour state HF exists as hexamer(HF)$\sf _{6}$ while H₂O exists as isolated molecules. It means that all the hydrogen bonds not be broken in HF.

The boiling point of H₂O is higher than that of NH₃ because

• Oxygen atom have more electro negativity and smaller size than nitrogen. Thus the strength of hydrogen bond is more in H₂O than NH₃.
• Even though H₂O forms less no of hydrogen bonds than NH₃ due to higher bond energy, the boiling point of H₂O is higher than that of NH₃