Frank Textbook Solutions: Metallurgy

 Page 1


Chapter 7. Metallurgy
Solution 9: 
 
PAGE NO : 152
Page 2


Chapter 7. Metallurgy
Solution 9: 
 
PAGE NO : 152
Solution 10: 
Solution 11: 
Solution 12:
1. Aqueous solution of sodium chloride is not used for electrolytic reduction of sodium metal because 
sodium metal formed at cathode after discharge of sodium ions( at cathode) will react with water 
to form alkali NaOH.
2. For the reduction of a metal oxide a reducing agent other than carbon is carbon monoxide (CO).
 
Page 3


Chapter 7. Metallurgy
Solution 9: 
 
PAGE NO : 152
Solution 10: 
Solution 11: 
Solution 12:
1. Aqueous solution of sodium chloride is not used for electrolytic reduction of sodium metal because 
sodium metal formed at cathode after discharge of sodium ions( at cathode) will react with water 
to form alkali NaOH.
2. For the reduction of a metal oxide a reducing agent other than carbon is carbon monoxide (CO).
 
Solution 13: 
Solution 1:
1. Gold and Platinum.
2. Charge.
3. Gangue.
4. Flux.
5. Calcination.
6. Roasting.
7. Iron pyrites.
8. Bauxite.
9. Cryolite, aluminium fluoride, Calcium fluoride.
10. Cathode: inner lining of gas-carbon of the electrolytic cell. 
Anode: Thick carbon rods dipping into the fused electrolytes.
11. Thermite welding.
12. Copper and silver.
13. Aluminium, Iron.
14. platinum and gold
15. sodium and potassium
Solution 2:
1. Zinc is used in galvanization and dry cells because zinc coating protects the iron from corrosion as 
it is more electropositive than iron hence it would be attacked first.
2. Nitric acid can be stored in aluminium containers because it do not attack aluminium. It renders 
aluminium passive due to the formation of an oxide film on surface of aluminum.
3. Aluminium oxide cannot be reduced by carbon because it is comparatively high in electrochemical 
series hence more reactive than carbon.
4. A neutral gas other than oxygen is formed at the anode during electrolysis of fused alumina 
because the oxygen gas formed at the anode oxidizes the carbon of the anode to carbon dioxide.
5. Extraction of aluminium was very difficult in the beginning because it was very expensive.
6. Carbon anodes are used in the electrolytic extraction of aluminium because carbon in the form of 
graphite is a good conductor of electricity.
7. Galvanized metal ions should not be used for storing food as food acids may react with the zinc 
coating and cause food poisoning.
Solution 3:
1. Mineral: The naturally occurring compounds of metals which are generally mixed with earthy such 
as soil, sand, limestone and rocks are known as minerals.
2. Ore: Those minerals from which a metal can be extracted profitably are called ores.
3. Gangue: The rocky impurities like (SiO
2
) present in an ore are called gangue.
4. Charge: The mixture of materials fed into a furnace to extract a metal is called charge.
5. Flux: The substance added to get rid of gangue in the extraction of metal is called flux.
6. Slag: The product obtained by the combination of gangue with flux is called slag.
PAGE NO : 169
Page 4


Chapter 7. Metallurgy
Solution 9: 
 
PAGE NO : 152
Solution 10: 
Solution 11: 
Solution 12:
1. Aqueous solution of sodium chloride is not used for electrolytic reduction of sodium metal because 
sodium metal formed at cathode after discharge of sodium ions( at cathode) will react with water 
to form alkali NaOH.
2. For the reduction of a metal oxide a reducing agent other than carbon is carbon monoxide (CO).
 
Solution 13: 
Solution 1:
1. Gold and Platinum.
2. Charge.
3. Gangue.
4. Flux.
5. Calcination.
6. Roasting.
7. Iron pyrites.
8. Bauxite.
9. Cryolite, aluminium fluoride, Calcium fluoride.
10. Cathode: inner lining of gas-carbon of the electrolytic cell. 
Anode: Thick carbon rods dipping into the fused electrolytes.
11. Thermite welding.
12. Copper and silver.
13. Aluminium, Iron.
14. platinum and gold
15. sodium and potassium
Solution 2:
1. Zinc is used in galvanization and dry cells because zinc coating protects the iron from corrosion as 
it is more electropositive than iron hence it would be attacked first.
2. Nitric acid can be stored in aluminium containers because it do not attack aluminium. It renders 
aluminium passive due to the formation of an oxide film on surface of aluminum.
3. Aluminium oxide cannot be reduced by carbon because it is comparatively high in electrochemical 
series hence more reactive than carbon.
4. A neutral gas other than oxygen is formed at the anode during electrolysis of fused alumina 
because the oxygen gas formed at the anode oxidizes the carbon of the anode to carbon dioxide.
5. Extraction of aluminium was very difficult in the beginning because it was very expensive.
6. Carbon anodes are used in the electrolytic extraction of aluminium because carbon in the form of 
graphite is a good conductor of electricity.
7. Galvanized metal ions should not be used for storing food as food acids may react with the zinc 
coating and cause food poisoning.
Solution 3:
1. Mineral: The naturally occurring compounds of metals which are generally mixed with earthy such 
as soil, sand, limestone and rocks are known as minerals.
2. Ore: Those minerals from which a metal can be extracted profitably are called ores.
3. Gangue: The rocky impurities like (SiO
2
) present in an ore are called gangue.
4. Charge: The mixture of materials fed into a furnace to extract a metal is called charge.
5. Flux: The substance added to get rid of gangue in the extraction of metal is called flux.
6. Slag: The product obtained by the combination of gangue with flux is called slag.
PAGE NO : 169
Solution 5:
1. Mercury.
2. Silver.
3. Zinc.
4. Aluminium.
Solution 6: 
As we know that minerals are the naturally occurring compounds of metals which are generally mixed 
with earthy such as soil, sand, limestone and rocks while ores are those minerals from which a metal 
can be extracted profitably. 
Hence “All ores are minerals but all minerals are not ores”.
Solution 7:
1. Iron: Haematite(Fe
2
O
3
) and Magnetite (Fe
3
O
4
).
2. Zinc: Zinc blende (ZnS) and Calamine (ZnCO
3
).
3. Aluminium:Bauxite(Al
2
O
3
) and Cryolite (AlF
3
.3NaF).
Solution 4: 
PAGE NO : 170 
Page 5


Chapter 7. Metallurgy
Solution 9: 
 
PAGE NO : 152
Solution 10: 
Solution 11: 
Solution 12:
1. Aqueous solution of sodium chloride is not used for electrolytic reduction of sodium metal because 
sodium metal formed at cathode after discharge of sodium ions( at cathode) will react with water 
to form alkali NaOH.
2. For the reduction of a metal oxide a reducing agent other than carbon is carbon monoxide (CO).
 
Solution 13: 
Solution 1:
1. Gold and Platinum.
2. Charge.
3. Gangue.
4. Flux.
5. Calcination.
6. Roasting.
7. Iron pyrites.
8. Bauxite.
9. Cryolite, aluminium fluoride, Calcium fluoride.
10. Cathode: inner lining of gas-carbon of the electrolytic cell. 
Anode: Thick carbon rods dipping into the fused electrolytes.
11. Thermite welding.
12. Copper and silver.
13. Aluminium, Iron.
14. platinum and gold
15. sodium and potassium
Solution 2:
1. Zinc is used in galvanization and dry cells because zinc coating protects the iron from corrosion as 
it is more electropositive than iron hence it would be attacked first.
2. Nitric acid can be stored in aluminium containers because it do not attack aluminium. It renders 
aluminium passive due to the formation of an oxide film on surface of aluminum.
3. Aluminium oxide cannot be reduced by carbon because it is comparatively high in electrochemical 
series hence more reactive than carbon.
4. A neutral gas other than oxygen is formed at the anode during electrolysis of fused alumina 
because the oxygen gas formed at the anode oxidizes the carbon of the anode to carbon dioxide.
5. Extraction of aluminium was very difficult in the beginning because it was very expensive.
6. Carbon anodes are used in the electrolytic extraction of aluminium because carbon in the form of 
graphite is a good conductor of electricity.
7. Galvanized metal ions should not be used for storing food as food acids may react with the zinc 
coating and cause food poisoning.
Solution 3:
1. Mineral: The naturally occurring compounds of metals which are generally mixed with earthy such 
as soil, sand, limestone and rocks are known as minerals.
2. Ore: Those minerals from which a metal can be extracted profitably are called ores.
3. Gangue: The rocky impurities like (SiO
2
) present in an ore are called gangue.
4. Charge: The mixture of materials fed into a furnace to extract a metal is called charge.
5. Flux: The substance added to get rid of gangue in the extraction of metal is called flux.
6. Slag: The product obtained by the combination of gangue with flux is called slag.
PAGE NO : 169
Solution 5:
1. Mercury.
2. Silver.
3. Zinc.
4. Aluminium.
Solution 6: 
As we know that minerals are the naturally occurring compounds of metals which are generally mixed 
with earthy such as soil, sand, limestone and rocks while ores are those minerals from which a metal 
can be extracted profitably. 
Hence “All ores are minerals but all minerals are not ores”.
Solution 7:
1. Iron: Haematite(Fe
2
O
3
) and Magnetite (Fe
3
O
4
).
2. Zinc: Zinc blende (ZnS) and Calamine (ZnCO
3
).
3. Aluminium:Bauxite(Al
2
O
3
) and Cryolite (AlF
3
.3NaF).
Solution 4: 
PAGE NO : 170 
Solution 8: 
Solution 9:
Refining of metals: It is the further purification of metals obtained by reduction process to remove all 
the impurities. 
Depending upon the nature of metal, nature of impurities and purpose for which metal is to be used. 
The three methods used for refining are:
1. Liquation.
2. Distillation.
3. Electrolytic refining.
Solution 10: