The correct order of boiling points for hydrogen halides is
A. HCl
B. HBr
C. HF
D. HI
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → HF > HI > HBr > HCl
From HCl to HI the molecules get larger, so the van der Waals forces and the boiling points increase. HF breaks the trend: its molecules are held together by strong intermolecular hydrogen bonds.
C. HF — first (highest): hydrogen bonding.
D. HI — second: the largest molecule of the other three, strongest van der Waals forces.
B. HBr — third.
A. HCl — last (lowest): the smallest molecule, weakest van der Waals forces.
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.
NCERT (Pre-rationalised edition, 2022-23):
Reactivity towards Hydrogen – …
