AP EAMCET2013ChemistryGeneral Principles and Processes of Isolation of Metals
Which of the following is not added during the extraction of silver by cyanide process?
Options
- ANaCN
- BAir
- CZn
- DNa ₂ ~S ₂ O ₃
Correct answer
D. Na ₂ ~S ₂ O ₃
Step-by-step solution
In the extraction of silver from cyanide process (also Mac-Arthur Forrest process), the siliver compound dissolve in NaCN solution forming a soluble complex salt, in presence of air, then silver is precipitated from this complex salt by the addition of Zn , because Zn being more reactive displaces the Ag. aligned Ag ₂ ~S +4 NaCN & 2 Na [ Ag ( CN )₂ ]+ Na ₂ ~S Na ₂ ~S +2 O ₂ & Na ₂ SO ₄ 2 Na [ Ag ( CN )₂ ]+ Zn & Na ₂ [ Zn ( CN )₄ ]+2 Ag aligned