Advertisements
Advertisements
Question
What is the role of zinc metal in the extraction of silver ?
Advertisements
Solution
Silver is extracted from the ore-argentite (Ag2S). This process of extraction of silver is called as cyanide process as sodium cyanide solution is used. The ore is crushed, concentrated and then treated with sodium cyanide solution. This reaction results into sodium argento cyanide Na[Ag(CN)2]. The reaction is as follows:
AgS + 4NaCN ⇌ 2Na[Ag(CN)2] + Na2S
The solution of sodium argento cyanide combines with zinc dust. It forms sodium tetra cyanozicate and precipitates silver. This precipitated silver is called as spongy silver. The reaction is as follows:
Zn + 2Na[Ag(CN)2] → Na2[Zn(CN)4] + 2Ag
The spongy silver is fused with potassium nitrate to get pure silver. This silver obtained is purified by electrolytic process.
APPEARS IN
RELATED QUESTIONS
What is calcination?
Explain calcination with reactions.
Reduction of metal oxide to metal becomes easier if the metal obtained is in liquid state. Why?
Name the processes from which chlorine is obtained as a by-product.
Which one of the following oxidation state of Manganese is unstable?
(a) + 2
(b) + 4
(c) + 5
(d) + 7
What is the action of carbon on the following metal oxides :
ZnO in the vertical retort furnace
Which metal is also found in sea beds?
In the extraction of chlorine by electrolysis of brine ______.
Which of the following reactions is an example of autoreduction?
Why are sulphide ores converted to oxide before reduction?
