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JEE Main202524 Jan 2025Evening ShiftChemistryd and f Block ElementsActual

Find the compound ' A ' from the following reaction sequences. A aqua-regia B [ (2) AcOH ] (1) KNO ₂ NH ₄ OH yellow ppt

Options

  1. ACoS
  2. BZnS
  3. CNiS
  4. DMnS

Correct answer

A. CoS

Step-by-step solution

Compound (A) in the given reaction sequence is likely to be CoS. aligned CoS + HNO ₃+3 HCl Co ²⁺ & + S + NOCl & +2 Cl ⁻+2 H ₂ O aligned The above solution is neutralised with NH ₄ OH . To a neutral solution of Co ²⁺ , acetic acid and saturated solution of KNO ₂ are added which results in the formation of yellow precipitate of K ₃ [ Co ( NO ₂ )₆ ] Co ²⁺+7 NO ₂⁻+2 H ⁺+3 ~K ⁺ K ₃ [ Co ( NO ₂ )₆ ]+ NO + H ₂ O

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