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JEE MainChemistryd and f Block Elements

When an acidified solution of potassium dichromate is treated with hydrogen peroxide in the presence of diethyl ether, the organic layer turns deep blue. The compound responsible for this blue colour is:

Options

  1. ACrO ₅
  2. BCr ₂ O ₃
  3. CCr ₂( SO ₄)₃
  4. DH ₂ CrO ₄

Correct answer

A. CrO ₅

Step-by-step solution

When an acidified solution of potassium dichromate reacts with hydrogen peroxide, chromium peroxide ( CrO ₅ ) is formed. Cr ₂ O ₇²⁻ + 2 H ^+ + 4 H ₂ O ₂ 2 CrO ₅ + 5 H ₂ O CrO ₅ is highly unstable in aqueous medium but gets extracted into organic solvents like diethyl ether or amyl alcohol, where it forms a stable, deep blue coloured complex. Answer: CrO ₅

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