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Most Important Selected Qs for JEE AdvancedChemistryd and f Block Elements

Which of the following statement(s) is (are) correct when a mixture of NaCl and K ₂ Cr ₂ O ₇ is gently warmed with conc. H ₂ SO ₄ ?

Options

  1. AA deep red vapour is evolved
  2. BThe vapour when passed through NaOH solution, gives a yellow solution
  3. CChiorine gas is also evolved
  4. DChromyl chioride is formed

Correct answer

D. Chromyl chioride is formed

Step-by-step solution

(A) When NaCl and K ₂ Cr ₂ O ₇ warmed with H ₂ SO ₄ (i.e. in acidic medium), they produce deep red vapours of chromyl chloride ( CrO ₂ Cl ₂ ) (B) When NaOH is passod, the product CrO₃ , formed In step (a) will react with NaOH and gives yellow colour solution (C) Chlorine gas is not evolved, thus false (D) In the given reaction, chromyl chloride ( CrO ₂ Cl ₂ ) is formed. All reactions are as follows (i) K ₂ Cr ₂ O ₇+2 H ₂ SO ₄ 2 KHSO ₄+2 CrO ₃+ H ₂ O (ii) NaCl + H ₂ SO ₄ NaHSO ₄+ HCl (iii) CrO ₃+2 HCl CrO ₂ Cl ₂ (iv

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