question_answer

  (a) Write a non exothermic reaction taking place in the blast furnace during extraction of iron. (b) What is flux? What is the role of flux in the metallurgy of copper? (c) Although thermo dynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of aluminium. Why?                                                                                                                         [3]

Answer:

  (a)                               [1] (b) Silica is used as flux and removes oxide impurities as CaO, MgO, FeO, in the form of and If copper sulphide mineral is rich in FeO, it is treated with flux and heated in a reverberatary furnace. FeO is removed as slag.                 [1] (c) The free energy change for the formation of  is highly negative thus no reducing agent is suitable for its reduction. to Thus, it is not feasible A] is obtained by electrolysis of oxide.                                         [1]