Question

Explain the role of NaCN in extraction of silver from silver ore??

Answer 1

The following reaction is involved in the extraction of silver after the silver ore has been leached with NaCN.
AgS+NaCN----2Na(Ag(CN)2)+Na2S

Answer 2

Answer: It converts metal ores to their soluble complexes

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.

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