Answer: HI > HBr > HCl > HF.
- A HF > HCl > HBr > HI
- B HI > HBr > HCl > HF
- C HCl > HF > HBr > HI
- D HBr > HI > HCl > HF
Correct answer: B. HI > HBr > HCl > HF
Explanation: Acidity rises down the group as the H–X bond weakens, so HI is the strongest and HF (with its strong bond and H-bonding) the weakest.
Xenon tetrafluoride (XeF4) has six electron domains around xenon — four Xe–F bonds plus two lone pairs. The lone pairs occupy opposite axial positions, leaving the four fluorine atoms in a square-planar shape (Xe–F ≈ 194 pm). Image: ChemSim, Public Domain, via Wikimedia Commons.
Concept context
Covers the nitrogen family (Group 15), oxygen family (Group 16), halogens (Group 17), and noble gases (Group 18). One of the highest-weightage inorganic chapters in NEET and JEE - includes preparation and properties of HNO₃, H₂SO₄, interhalogens, and xenon compounds.