Question

Zn and S are heated to form zinc sulphide. If 12 g of Zn is heated with 7.5 g of S, the amount of product formed is (molar mass of Zn = 65, S = 32):

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

$Zn+S\to ZnS$
Calculation of limiting reagent:
65 g of Zn reacts with = 32g of S
$\therefore$ 12g Zn reacts with = $\frac{32}{65}\times 12=5.9gofS$
Hence, Zn is the limiting reagent.
Mass of ZnS formed:
65g of Zn produces = 97g of Zns
$\therefore$ 12g of Zn produces = $\frac{97}{65}\times 12=17.9gofZns$