Question

(i) In how many steps, is impure metal obtained from concentrated sulphide ore?

Hint:

The process of extracting impure metal from its sulphide ore involves roasting to convert sulphide into oxide, followed by reduction to obtain pure metal.

Answer 1

Impure metal obtained from concentrated sulphide ore is generally done in two main steps: 1. Roasting:
The concentrated sulphide ore is heated in excess air at high temperatures. During this process, the sulphide ore is converted into the oxide form, and sulfur dioxide gas is released. This is called roasting. \[ \text{2ZnS (s)} + \text{3O}_2 (g) $\rightarrow$ \text{2ZnO (s)} + \text{2SO}_2 (g) \] The resulting zinc oxide is impure. 2. Reduction:
The zinc oxide is then reduced by heating it with carbon (usually coke) at high temperatures to produce pure zinc metal and carbon dioxide gas. This is called reduction. \[ \text{ZnO (s)} + \text{C (s)} $\rightarrow$ \text{Zn (s)} + \text{CO}_2 (g) \] Thus, impure metal is obtained from sulphide ore in two steps: roasting and reduction.