Question

The variation of the boiling points of the hydrogen halides is in the order $HF > HI > HBr > HCl$. What explains the higher boiling point of hydrogen fluoride ?

• A. The bond energy of HF molecules is greater than in other hydrogen halides
• B. The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule
• C. The electronegativity of fluorine is much higher than for other elements in the group.
• D. There is strong hydrogen bonding between HF molecules

Answer 1

Answer: (D)

There is strong hydrogen bonding between HF molecules

Answer 2

Due to strong H-bonding in HF molecule, boiling point is highest for HF
HF > HI > HBr > HI