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Question 880008
JEE Chemistry · Hard

s-Block Elements: Mixed MCQ

Solve this quality-checked JEE multiple-choice question, then review the correct answer and explanation.

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MixedHardQuestion 880008

Question

Bleaching powder (CaOCl₂ or Ca(OCl)Cl) on treatment with CO₂ releases:
  1. A
    Cl₂ gas (which does the bleaching)
    Correct
  2. B
    CO₂ remains unchanged
  3. C
    CaCO₃ + HCl
  4. D
    Ca(OH)₂ + Cl₂

Correct answer

Cl₂ gas (which does the bleaching)

Explanation

Bleaching powder + dilute acid/CO₂: Ca(OCl)Cl + CO₂ + H₂O → CaCO₃ + Cl₂ + H₂O (or with HCl → CaCl₂ + H₂O + Cl₂). The liberated Cl₂ oxidises coloured matter → bleaching. The reaction with CO₂ in air explains why bleaching powder loses potency on storage.

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