Answer the following questions briefly: (i). What is the actual reducing agent of haematite in blast furnace? (ii). Zinc, not copper is used for the recovery of metallic silver from the complex [Ag(CN)_2]^(ɵ), explain. (iii). Why is chalcocite roasted and not calcinated during the recovery of copper?

Answer the following questions briefly: (i). What is the actual reduc

1.	Answer the following questions briefly: (i). What is the actual reducing agent of haematite in blast furnace? (ii). Zinc, not copper is used for the recovery of metallic silver from the complex [Ag(CN)_2]^(ɵ), explain. (iii). Why is chalcocite roasted and not calcinated during the recovery of copper?
Answer» Solution :(i). For iron, first by calcination and roasting the ferrous oxide is oxidised to FERRIC. Then in blast furnace, Smelting is done where it is reduced to iron. `4FeO+O_2to2Fe_2O_3` `Fe_2O_3+COto2Fe_3O_4+CO_2` `Fe_2O_3+COto2FeO+CO_2` `FeO+COtoFe+CO_2` Carbon monoxide is the actual reducing AGENT of haematite in blast furnace. (ii). Zinc is more reducing and CHEAPER than copper. (iii). Chalcocite is a sulphide ore of copper therefore it must be ROASTED in the presence of air to get oxide.