In the extraction of silver by the MacArthur cyanide process
CHEMISTRY · Single correct · CBSE · Chemistry · Metals and Non-metals · Metals and Non-metals
Problem
In the extraction of silver by the MacArthur cyanide process, a small amount of KNO3 is also added as a flux. The function of KNO3 is
(1) To oxidise Ag in the native form to Ag+
(2) To oxidise lead and zinc impurities
(3) To form a complex with Ag+, which is then reduced to metallic silver using zinc
(4) To oxidise the sulphur in argentite ore to SO2, which escapes from the reaction