wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Explain the role of each of the following.
(i) NaCN in the extraction of silver
(ii) SiO2 in the extraction of copper

Open in App
Solution

I) In the extraction of gold and silver the metal is leached with NaCN and KCN, which is a oxidation reaction.
4M+8CN+2H2O+O24[M(CN)2]+4OH
In the next step, the compound is reacted with zinc leading to the formation of metal.
4[M(CN)2]+Zn[Zn(CN)4]2+2M
M is Ag or Au.
II) The role of silica(SiO2) in the extraction of copper is to remove the FeO obtained in roasting. So, silica is added before roasting as flux to remove iron impurity. So, FeO reacts with silica leading to form ferrous silicate as slag.
FeO+SiO2FeSiO3

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Cyanide or MacArthur Forrest Process
CHEMISTRY
Watch in App
Join BYJU'S Learning Program
CrossIcon