Question

Native silver metal forms a water soluble complex with a dilute aqueous solution of NaCN in the presence of

Solution

Correct option is

Oxygen

 

A water soluble complex of silver with a dilute aqueous solution of NaCN is sodium argentocyanide. In the cyanide process, the native form is crushed and treated with 0.1 – 0.2% solution of NaCN and aerated.

   

Argentocyanide is soluble. Further metal is recovered from the complex by reduction with zinc.

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