The chief ore of Zn is the sulphide, ZnS. The ore is concentrated by froth floatation process and then heated in air to convert ZnS to ZnO.(i) 2ZnS+ 3O2 →80% 2ZnO + 2SO2(ii) ZnO+ H2SO4 →100% ZnSO4 + H2O(iii) 2ZnSO4 + 2H2O →80% 2Zn + 2H2SO4+O2The number of moles of ZnS required for producing 2 moles of Zn will be