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ICSE Class 10 Chemistry Question 6 of 64

Metallurgy — Question 1

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Question 1

Extraction of Metals — General details of stages involvedComplete and balance the equation
Step 1 : Dressing of the ore   
Step 2 : Conversion of conc. ore to its oxide   
Roasting of sulphide ore   
1. Roasting of zinc blendeZnS+O2→800°C...............+...............[g]\text{ZnS} + \text{O}_2 \xrightarrow{800 \degree\text{C}} ............... + ............... [\text{g}]
2. Roasting of iron pyriteFeS2+O2→...............+...............[g]\text{FeS}_2 + \text{O}_2 \rightarrow ............... + ............... [\text{g}]
Calcination of carbonate ore   
3. Calcination of zinc carbonateZnCO3→<400°C...............+...............[g]\text{ZnCO}_3 \xrightarrow{\lt 400 \degree\text{C}} ............... + ............... [\text{g}]
4. Calcination of iron [II] carbonateFeCO3→...............+...............[g]\text{FeCO}_3 \rightarrow ............... + ............... [\text{g}]
Step 3: Reduction of metallic oxide to its oxide 
Reduction by electrolysis 
5. Electrolytic reduction of pure aluminaAl2O3 ⇌ ............... + ...............
6. At cathode2Al3+ + 6e- ⟶ ...............
Reduction by reducing agents [C, CO, H2] 
7. Reduction of zinc oxide - by cokeZnO+C→Δ...............+...............[g]\text{ZnO} + \text{C} \xrightarrow{\Delta} ............... + ............... [\text{g}]
8. Reduction of iron [III] oxide - by COFe2O3+CO→Δ...............+...............[g]\text{Fe}_2\text{O}_3 + \text{CO} \xrightarrow{\Delta} ............... + ............... [\text{g}]
9. Reduction of lead [II] oxide - by cokePbO+C→Δ...............+...............[g]\text{PbO} + \text{C} \xrightarrow{\Delta} ............... + ............... [\text{g}]
10. Reduction of copper [II] oxide - by cokeCuO+C→Δ...............+...............[g]\text{CuO} + \text{C} \xrightarrow{\Delta} ............... + ............... [\text{g}]
11. Reduction of copper [II] oxide - by hydrogenCuO+H2→Δ...............+...............[g]\text{CuO} + \text{H}_2 \xrightarrow{\Delta} ............... + ............... [\text{g}]
Reduction by thermal decomposition
12. Thermal decomposition of mercury [II] oxideHgO→Δ...............+...............[g]\text{HgO} \xrightarrow{\Delta} ............... + ............... [\text{g}]
13. Thermal decomposition of silver [I] oxideAg2O→Δ...............+...............[g]\text{Ag}_2\text{O} \xrightarrow{\Delta} ............... + ............... [\text{g}]
Step 4: Electrorefining of impure metals 
Answer
Extraction of Metals — General details of stages involvedComplete and balance the equation
Step 1 : Dressing of the ore   
Step 2 : Conversion of conc. ore to its oxide   
Roasting of a sulphide ore   
1. Roasting of zinc blende2ZnS+3O2→800°C2ZnO+2SO2[g]2\text{ZnS} + 3\text{O}_2 \xrightarrow{800 \degree\text{C}} \bold{2ZnO} + \bold{2SO}_\bold{2}[\text{g}]
2. Roasting of iron pyrite4FeS2+11O2→2Fe2O3+8SO2[g]4\text{FeS}_2 + 11\text{O}_2 \rightarrow \bold{2Fe}_\bold{2}\bold{O}_\bold{3} + \bold{8SO}_\bold{2} [\text{g}]
Calcination of a carbonate ore   
3. Calcination of zinc carbonateZnCO3→<400°CZnO+CO2[g]\text{ZnCO}_3 \xrightarrow{\lt 400 \degree\text{C}} \bold{ZnO} + \bold{CO}_\bold{2} [\text{g}]
4. Calcination of iron [II] carbonateFeCO3→FeO+CO2[g]\text{FeCO}_3 \rightarrow \bold{FeO} + \bold{CO}_\bold{2} [\text{g}]
Step 3: Reduction of metallic oxide to its oxide 
Reduction by electrolysis 
5. Electrolytic reduction of pure aluminaAl2O3 ⇌ 2Al3+ + 3O2-
6. At cathode2Al3+ + 6e- ⟶ 2Al
Reduction by reducing agents [C, CO, H2] 
7. Reduction of zinc oxide - by cokeZnO+C→ΔZn+CO[g]\text{ZnO} + \text{C} \xrightarrow{\Delta} \bold{Zn} + \bold{CO} [\text{g}]
8. Reduction of iron [III] oxide - by COFe2O3+3CO→Δ2Fe+3CO2[g]\text{Fe}_2\text{O}_3 + 3\text{CO} \xrightarrow{\Delta} \bold{2Fe} + \bold{3CO}_\bold{2} [\text{g}]
9. Reduction of lead [II] oxide - by coke2PbO+C→Δ2Pb+CO2[g]2\text{PbO} + \text{C} \xrightarrow{\Delta} \bold{2Pb} + \bold{CO}_\bold{2} [\text{g}]
10. Reduction of copper [II] oxide - by cokeCuO+C→ΔCu+CO[g]\text{CuO} + \text{C}\xrightarrow{\Delta} \bold{Cu} + \bold{CO} [\text{g}]
11. Reduction of copper [II] oxide - by hydrogenCuO+H2→ΔCu+H2O[g]\text{CuO} + \text{H}_2 \xrightarrow{\Delta} \bold{Cu} + \bold{H}_\bold{2}\bold{{O}} [\text{g}]
Reduction by thermal decomposition 
12. Thermal decomposition of mercury [II] oxide2HgO→Δ2Hg+O2[g]2\text{HgO} \xrightarrow{\Delta} \bold{2Hg} + \bold{O}_\bold{2} [\text{g}]
13. Thermal decomposition of silver [I] oxide2Ag2O→Δ4Ag+O2[g]2\text{Ag}_2\text{O} \xrightarrow{\Delta} \bold{4Ag} + \bold{O}_\bold{2} [\text{g}]
Step 4: Electrorefining of impure metals