Question

Zinc blende is roasted in air. Calculate the number of moles of sulphur dioxide liberated by 776 g of ZnS.

• A. 4 moles
• B. 6 moles
• C. 8 moles
• D. 2 moles

Answer 1

Answer: (C)

8 moles

$2ZnS+3O_2\to 2ZnO+2S{O}_2$
Moles of ZnS=$\frac{776}{97}=8$
2 moles of ZnS produces 2 moles of $S{O}_2$.

So, 8 moles of ZnS produces 8 moles of $S{O}_2$.

So, moles of $S{O}_2$ obtained = 8.