Answer: H2SO4 with dissolved SO3 (pyrosulfuric acid, H2S2O7).
- A H2SO4 with dissolved SO3 (pyrosulfuric acid, H2S2O7)
- B Generally dilute aqueous H2SO4 at low concentration
- C H2SO4 existing largely as a gas under ordinary conditions
- D A direct mixture of concentrated H2SO4 with concentrated HNO3
Correct answer: A. H2SO4 with dissolved SO3 (pyrosulfuric acid, H2S2O7)
Explanation: Oleum is formed when SO3 is dissolved in concentrated H2SO4: SO3 + H2SO4 → H2S2O7 (pyrosulfuric acid).
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.