JEE Advanced levelSingle correct optionDifficulty 3 of 3mt053
194kg of a zinc ore containing 60.0%ZnS is roasted completely to ZnO (2ZnS+3OX22ZnO+2SOX2). The oxide is leached with dilute acid, ZnO+HX2SOX4ZnSOX4+HX2O, with 95.0% of the oxide dissolving. Electrowinning then deposits 90.0% of the dissolved zinc as metal. With Zn=65, S=32, O=16, H=1, the mass of HX2SOX4 consumed in leaching and the mass of zinc deposited are
A117.60 kg and 66.69 kg
B111.72 kg and 74.10 kg
C111.72 kg and 66.69 kg
D223.44 kg and 66.69 kg
Answer: C
Moles of ZnS =116400/97=1200, giving 1200 mol ZnO. Dissolved =0.95×1200=1140 mol, so HX2SOX4=1140×98=111.72kg. Zinc deposited =0.90×1140=1026 mol ×65=66.69kg.