JEE Main · 2019 · 09 Apr 2019 · Shift 2 · Chemical Bonding and Molecular Structure

HF has highest boiling point among hydrogen halides, because it has:

(A)lowest dissociation enthalpy
(B)strongest van der Waals' interactions
(C)strongest hydrogen bonding✓ Correct
(D)lowest ionic character

Answer: (C)

Solution

Among the hydrogen halides, HF stands apart because fluorine is so strongly electronegative that neighbouring

HF

molecules associate through unusually strong hydrogen bonds. Breaking that extensive hydrogen bonding demands a great deal of energy, which is why HF boils far higher than HCl, HBr or HI despite its smaller molecular mass.

JEE Main · 2019 · 09 Apr 2019 · Shift 2 · Single correct option

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