Answer: platinum–rhodium gauze.
- A iron granules
- B platinum–rhodium gauze
- C vanadium pentoxide
- D finely divided nickel
Correct answer: B. platinum–rhodium gauze
Explanation: The Ostwald process burns NH₃ over a hot platinum–rhodium gauze to form NO, later oxidised and absorbed in water to give HNO₃.
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.