Question:
Write the chemical reactions involved in the extraction of gold by the cyanide process. Also, give the role of zinc in the extraction.
Solution:
4Au(s) + 8CN– (aq) + 2H2O(aq) + O2(g) → 4[Au(CN)2] – (aq) + 4OH– (aq)
2[Au(CN)2] – (aq) + Zn(s) → 2Au(s) + [Zn(CN)4] 2– (aq)
Zinc places the role of a reducing agent. It reduces Au+ to pure Au.
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.