KCET 2020 Chemistry Solved Paper

The formula of copper pyrites is CuFeS2. In auto reduction, the sulphide ores of the metals which are less electropositive like Hg,Pb and Cu are heated in air so as to convert a part of it to its oxides.
These oxides then reacts with the remaining sulphide ore in the absence of air, to give the metal and sulphur dioxide. The corresponding reaction is:
Cu2O+

1

2

Cu2S→3Cu+

1

2

SO2