Answer: Nascent oxygen released from Cl2 + H2O reaction oxidising the colour.
- A Nascent oxygen released from Cl2 + H2O reaction oxidising the colour
- B The hydrochloric acid formed alongside the bleaching reaction
- C Cl2 acting as a reducing agent that donates electrons to the dye
- D Cl2 simply dissolving in water without any further chemical change
Correct answer: A. Nascent oxygen released from Cl2 + H2O reaction oxidising the colour
Explanation: Cl2 + H2O → HOCl + HCl; HOCl → HCl + [O] (nascent oxygen). The nascent oxygen bleaches by oxidising coloured compounds.

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.