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JEE MainChemistryd and f Block Elements

A blackish-brown solid 'X' fuses with an alkali metal hydroxide in the presence of an oxidizing agent to produce a dark green compound 'Y'. Compound 'Y' on electrolytic oxidation in an alkaline medium gives a dark purple compound 'Z'. The oxidation states of manganese in compounds X, Y, and Z respectively are:

Options

  1. A+4, +7, +6
  2. B+4, +6, +7
  3. C+4, +5, +7
  4. D+4, +7, +7

Correct answer

B. +4, +6, +7

Step-by-step solution

The blackish-brown solid 'X' is pyrolusite ore, MnO ₂ . Here, the oxidation state of Mn is +4 . When fused with an alkali metal hydroxide (like KOH ) and an oxidizing agent (like KNO ₃ or O ₂ ), it forms a dark green compound 'Y', which is potassium manganate, K ₂ MnO ₄ . The oxidation state of Mn in K ₂ MnO ₄ is +6 . Electrolytic oxidation of K ₂ MnO ₄ in an alkaline medium yields the dark purple compound 'Z', which is potassium permanganate, KMnO ₄ . The oxidation state of Mn in KMnO ₄ is +7 . Thus, the oxidation

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