CBSE Class 10 Answered
- The moderately reactive metals in the middle of the reactivity series are extracted by the reduction
- It is easier to obtain metals from their oxides (by reduction) than from carbonates or sulphides.
- The concentrated ores can be converted into metal oxides by the process of calcination or roasting.
- Calcination :
For example:
When zinc carbonate is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
ZnCO3(s) → ZnO(s) + CO2(g)
2. Roasting is the process in which a sulphide ore is strongly heated in the presence of air to convert it into a metal oxide.
2ZnS(s) + 3O2(g) → 2ZnO(s) + 2SO2(g)
The metal oxides are converted to free metal by using reducing agents such as carbon, aluminium, sodium or calcium.
For example:
Zinc metal is extracted by the reduction of zinc oxide with carbon.
Thus, when zinc oxide is heated with carbon, zinc metal is produced.
ZnO(s) + C(s) → Zn(s) + CO(g)