Answer: [Fe(H2O)5NO]2+.
- A [Fe(H2O)6]3+
- B [Fe(H2O)5NO]2+
- C [Fe(NO)2]2+
- D [Fe(H2O)5(OH)]2+
Correct answer: B. [Fe(H2O)5NO]2+
Explanation: In the brown ring test, NO reduced from the nitrate combines with Fe2+ to form the brown complex [Fe(H2O)5NO]2+ in which iron is in the +1 state.
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.