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NEET2003Chemistryd and f Block ElementsActual

Assertion : Solution of Na ₂ CrO ₄ in water is coloured. Reason: Oxidation state of Cr in Na ₂ CrO ₄ is +6 .

Options

  1. AIf both assertion and reason are true and the reason is the correct explanation of the assertion
  2. BIf both assertion and reason are true and the reason is not the correct explanation of the assertion
  3. CIf assertion is true but reason is false
  4. DIf both assertion and reason are false.

Correct answer

B. If both assertion and reason are true and the reason is not the correct explanation of the assertion

Step-by-step solution

Na ₂ CrO ₄ solution in water is yellow in colour, when acidified changes to orange colour (due to the formation of Cr ₂ O ₇²⁻ ions). Na ₂ CrO ₄+ H ₂ SO ₄ Na ₂ Cr ₂ O ₇+ Na ₂ SO ₄+ H ₂ O Oxidation state : Na ₂ CrO ₄ Let oxidation state of Cr be x . 2(+1)+x+4(-2)=0 x=+6 .

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