(i) On passing current through the electrolytic cell the pure metal gets deposited on the cathode.
(ii) evolution of SO2 gas
(iii) It selectively prevents one of the sulphide ores from coming to the froth.
Detailed Answer:
(i) On passing current through the electrolytic cell the pure metal gets deposited on the cathode.
(ii) Copper pyrites is concentrated by froth floatation process. The molten copper is poured and cooled. The sulphur dioxide evaluating from the melt gets trapped in the cooler parts of the surface giving a blistery appearance.
(iii) The role of depressants is to separate two sulphide ores by selectively preventing ore from forming froth.
