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QJEEM22Ch1fb1: JEE Main 2022 Chemistry - Class 12 JEEM22Ch1fb1 Solution: Leaching of gold with dilute aqueous solution of NaCN in…

Leaching of gold with dilute aqueous solution of NaCN in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are :

Multiple Choice Options

  • A [Au(CN)4]− and [Zn(CN)2(OH)2]2−
  • B [Au(CN)2]− and [Zn(OH)4]2−
  • C [Au(CN)2]− and [Zn(CN)4]2−
  • D [Au(CN)4]2− and [Zn(CN)6]4−

Step-by-Step Verified Solution

In the metallurgy of gold

4Au+8CN−+2H2O+O2→4[Au(CN)2]−+4OH−

2[Au(CN)2]−+Zn→[Zn(CN)4]2−+2Au

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