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NEETChemistryd and f Block Elements

Which of the following statements regarding the highest oxides of 3d transition metals is incorrect?

Options

  1. AMn₂O₇ is an acidic oxide and is a covalent green oil at room temperature.
  2. BCrO₃ is a basic oxide that dissolves in dilute acids to give Cr³⁺ ions.
  3. CV₂O₅ is amphoteric but predominantly acidic, and is widely used as a catalyst.
  4. DThe highest oxidation number in the oxides of 3d metals coincides with their group number and is attained in S

Correct answer

B. CrO₃ is a basic oxide that dissolves in dilute acids to give Cr³⁺ ions.

Step-by-step solution

The statement in option 2 is incorrect. As the oxidation state of a metal increases, its ionic character decreases and its acidic character increases. In CrO₃ , chromium is in its highest oxidation state ( +6 ), making it an acidic oxide, not a basic one. It dissolves in water to give chromic acid ( H₂CrO₄ ) and dichromic acid ( H₂Cr₂O₇ ). The other statements are correct facts from NCERT: Mn₂O₇ is a covalent green oil and is highly acidic. V₂O₅ is amphoteric but mainly acidic. The highest oxidation number in the o

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