Question

What is the role of nacn in the extraction of silver from a silver ore?

Answer 1

NaCn is use for leaching of Ag ore in the presence of air from which the silver is obtained later by replacement.

4Ag + 8CN- + 2H2O + O2 → 4 [Ag(CN)2-] + 4OH-

Answer 2

Answer: To convert the silver ore into its soluble complex.

Explanation:-

$NaCN$ is used to extract precious metals like silver and gold by converting these metals or their ores into their soluble complexes by the process called as leaching.

In this process, the finely powdered argentite $Ag_2S$ or silver is treated with a dilute solution of sodium cyanide while a current of air is continuously passed. As a result, silver get oxidized which then combine with $CN^-$ ion forming their respective soluble complex cyanides while the impurities remain unaffected which are filtered off.

$4Ag+8NaCN+2H_2O+O_2\rightarrow 4Na[Ag(CN)_2](soluble complex)+4NaOH$