The Chief ore of Zinc is Zinc sulphide (Zns).
 $ZnS+O_2\to ZnO+S{O}_2\left(80\%yield\right)$
 $ZnO+H_{2}S{O}_4\to ZnS{O}_4+H_{2}O\left(100\%yield\right)$
 $ZnS{O}_4+H_{2}O\to Zn+H_{2}S{O}_4+O_2\left(60\%yield\right)$
The number of moles of ZnS required for producing 2.4 moles of Zn is