KCET2007ChemistryGeneral Principles and Processes of Isolation of Metals
During the extraction of gold the following reactions take place aligned Au + CN ⁻+ H ₂ O O ₂ [X] [X]+ Zn [Y]+ Au aligned X and Y are respectively
Options
- A[ Au ( CN )₂ ]⁻ and [ Zn ( CN )₆ ]⁴⁻
- B[ Au ( CN )₄ ]²⁻ and [ Zn ( CN )₄ ]²⁻
- C[ Au ( CN )₄ ]³⁻ and [ Zn ( CN )₄ ]²⁻
- D[ Au ( CN )₂ ]⁻ and [ Zn ( CN ₄ ) ]²⁻
Correct answer
D. [ Au ( CN )₂ ]⁻ and [ Zn ( CN ₄ ) ]²⁻
Step-by-step solution
aligned &4 Au +8 CN ⁻+2 H ₂ O + O ₂ &4 [ Au ( CN )₂ +4 OH ⁻ . & Soluble &2 [ Au ( CN )₂ + Zn 2 Au (s) + [ Zn ( CN )₄ ]²⁻ . aligned