Answer: NO and NO 2 (NOx from supersonic aircraft).
- A NO and NO<sub>2</sub> (NOx from supersonic aircraft)
- B N<sub>2</sub>O<sub>5</sub>, a stable nitrogen oxide that does not catalyse ozone breakdown
- C HNO<sub>3</sub>, the stable acid formed in the lower atmosphere from NOx
- D NH<sub>3</sub>, a basic gas with no catalytic effect on stratospheric ozone
Correct answer: A. NO and NO<sub>2</sub> (NOx from supersonic aircraft)
Explanation: NO reacts with O<sub>3</sub>: NO + O<sub>3</sub> → NO<sub>2</sub> + O<sub>2</sub>; then NO<sub>2</sub> + O → NO + O<sub>2</sub>. Net: O<sub>3</sub> + O → 2O<sub>2</sub>. NO is regenerated and catalyses ozone destruction.
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.