ROUTERA


Chapter 6 General Principles and Processes of Isolation of Elements

Class 12th Chemistry Chapter MCQs


1. What is the main purpose of the process of refining in metallurgy?

a) To remove impurities from the metal
b) To increase the metal's mass
c) To decrease the metal's mass
d) To make the metal impure
Answer: a) To remove impurities from the metal
Explanation: Refining is done to purify metals by removing impurities.


2. Which of the following is used in the extraction of copper from its ore?

a) Zinc
b) Lead
c) Iron
d) Carbon
Answer: d) Carbon
Explanation: Copper is extracted by smelting its ore (copper(I) sulfide) with carbon in a furnace.


3. Which of the following is the first step in the extraction of metals from their ores?

a) Refining
b) Roasting
c) Concentration of ores
d) Electrolysis
Answer: c) Concentration of ores
Explanation: The first step in metallurgy is to concentrate the ore to remove impurities.


4. What is the process of heating an ore in the presence of air to convert it into its oxide called?

a) Calcination
b) Roasting
c) Smelting
d) Leaching
Answer: b) Roasting
Explanation: Roasting is the process of heating an ore in excess air to convert the metal sulfide into an oxide.


5. Which of the following is the most commonly used method for concentrating bauxite ore?

a) Froth flotation
b) Leaching
c) Magnetic separation
d) Hydraulic washing
Answer: b) Leaching
Explanation: Bauxite ore is concentrated by leaching with sodium hydroxide.


6. What is the main product obtained from the reduction of iron ore in a blast furnace?

a) Iron
b) Steel
c) Oxygen
d) Hydrogen
Answer: a) Iron
Explanation: Iron is obtained from iron ore in the blast furnace by the reduction of iron oxides using coke.


7. In the extraction of gold, the process of separating gold from impurities using a solution of sodium cyanide is called:

a) Leaching
b) Roasting
c) Froth flotation
d) Amalgamation
Answer: a) Leaching
Explanation: Gold is extracted by leaching it with a sodium cyanide solution.


8. Which of the following metals can be extracted using the electrolytic reduction process?

a) Iron
b) Copper
c) Sodium
d) Lead
Answer: c) Sodium
Explanation: Sodium is extracted by electrolysis of molten sodium chloride.


9. Which of the following methods is used to extract metals like aluminum from their ores?

a) Electrolytic reduction
b) Carbon reduction
c) Roasting
d) Leaching
Answer: a) Electrolytic reduction
Explanation: Aluminum is extracted from bauxite ore using electrolysis in the Hall-Héroult process.


10. Which of the following metals is obtained by the process of thermite reaction?

a) Iron
b) Aluminium
c) Zinc
d) Copper
Answer: a) Iron
Explanation: The thermite reaction is used to produce iron by reducing iron oxide with aluminium powder.


11. Which of the following is the process of extracting a metal from its ore by using heat and a reducing agent like carbon?

a) Electrolysis
b) Calcination
c) Roasting
d) Reduction
Answer: d) Reduction
Explanation: Reduction is the process of extracting metals by heating the ore with a reducing agent like carbon.


12. Which of the following processes is used for the extraction of zinc from its ore?

a) Roasting
b) Reduction with carbon
c) Electrolytic reduction
d) Froth flotation
Answer: b) Reduction with carbon
Explanation: Zinc is extracted by reducing zinc oxide with carbon.


13. In the extraction of copper, which of the following ores is first concentrated by froth flotation?

a) Copper pyrite
b) Hematite
c) Bauxite
d) Galena
Answer: a) Copper pyrite
Explanation: Copper pyrite is concentrated by froth flotation to remove gangue.


14. Which of the following is an example of a metal obtained by the process of displacement reaction?

a) Iron
b) Zinc
c) Copper
d) Silver
Answer: b) Zinc
Explanation: Zinc is extracted from its ores by a displacement reaction.


15. The reduction of which of the following metal oxides can be carried out by using carbon?

a) Gold oxide
b) Copper oxide
c) Magnesium oxide
d) Sodium oxide
Answer: b) Copper oxide
Explanation: Copper oxide is reduced to copper by heating it with carbon.


16. Which of the following metals is extracted from its ore by the process of amalgamation?

a) Copper
b) Gold
c) Iron
d) Aluminium
Answer: b) Gold
Explanation: Gold is extracted using mercury in the process of amalgamation.


17. Which of the following is the correct order of reactivity of metals with respect to their extraction?

a) Alkali metals > Transition metals > Noble metals
b) Noble metals > Transition metals > Alkali metals
c) Transition metals > Alkali metals > Noble metals
d) Noble metals > Alkali metals > Transition metals
Answer: a) Alkali metals > Transition metals > Noble metals
Explanation: Alkali metals are the most reactive, followed by transition metals, and then noble metals which are the least reactive.


18. Which of the following ores is primarily used for the extraction of iron?

a) Bauxite
b) Haematite
c) Malachite
d) Copper pyrite
Answer: b) Haematite
Explanation: Haematite is the main ore used for the extraction of iron.


19. Which of the following statements about the extraction of metals is correct?

a) Electrolytic reduction is used for the extraction of low reactivity metals.
b) High reactivity metals are extracted by heating with carbon.
c) Metals like sodium and calcium are extracted by electrolysis.
d) Electrolysis is used to extract only non-metals.
Answer: c) Metals like sodium and calcium are extracted by electrolysis.
Explanation: High reactivity metals like sodium and calcium are extracted by electrolytic reduction.


20. What is the primary use of the process of froth flotation in metallurgy?

a) Separation of pure metals from ores
b) Removal of impurities from ores
c) Concentration of ores
d) Electrolytic extraction of metals
Answer: c) Concentration of ores
Explanation: Froth flotation is used to concentrate ores by separating valuable minerals from gangue.


21. Which of the following ores is used in the extraction of aluminum?

a) Haematite
b) Bauxite
c) Galena
d) Zinc blende
Answer: b) Bauxite
Explanation: Bauxite is the main ore used for the extraction of aluminum.


22. Which of the following is used to reduce metals from their oxides in the blast furnace?

a) Hydrogen
b) Carbon monoxide
c) Oxygen
d) Nitrogen
Answer: b) Carbon monoxide
Explanation: Carbon monoxide is used in the blast furnace to reduce metal oxides.


23. Which of the following metals is obtained by the electrolytic reduction of its ore in molten state?

a) Copper
b) Magnesium
c) Iron
d) Sodium
Answer: d) Sodium
Explanation: Sodium is extracted from molten sodium chloride using electrolysis.


24. Which of the following methods is used to extract silver from its ore?

a) Electrolysis
b) Froth flotation
c) Cyanide process
d) Roasting
Answer: c) Cyanide process
Explanation: Silver is extracted using the cyanide process, where it forms a soluble complex with cyanide ions.


25. What is the main use of the process of calcination?

a) To extract metals from ores
b) To concentrate ores
c) To reduce metal oxides to metals
d) To convert metal carbonates to oxides
Answer: d) To convert metal carbonates to oxides
Explanation: Calcination is the heating of ores in the absence of air to convert metal carbonates into metal oxides.


26. Which of the following metals can be extracted from its ore by the process of electrolysis?

a) Copper
b) Zinc
c) Iron
d) Sodium
Answer: d) Sodium
Explanation: Sodium is extracted by electrolysis of molten sodium chloride.


27. Which of the following ores is used for extracting copper?

a) Hematite
b) Malachite
c) Bauxite
d) Galena
Answer: b) Malachite
Explanation: Malachite is one of the ores from which copper is extracted.


28. Which of the following is a key component in the extraction of aluminium?

a) Hall-Héroult process
b) Thermite reaction
c) Cyanide process
d) Froth flotation
Answer: a) Hall-Héroult process
Explanation: The Hall-Héroult process is used for the extraction of aluminum through electrolysis of bauxite.


29. Which of the following methods is used to separate iron from its ore in a blast furnace?

a) Electrolysis
b) Roasting
c) Carbon reduction
d) Leaching
Answer: c) Carbon reduction
Explanation: In a blast furnace, iron ore is reduced to iron using carbon.


30. Which of the following is true about the extraction of metals?

a) Metals with low reactivity can be extracted by heating with carbon.
b) Highly reactive metals cannot be extracted by electrolysis.
c) Noble metals are extracted by reduction with carbon.
d) Metals are extracted only from their ores by heating with air.
Answer: a) Metals with low reactivity can be extracted by heating with carbon.
Explanation: Metals like iron and copper can be extracted by heating with carbon as they are less reactive.


31. In the extraction of copper, which of the following processes is used after concentration?

a) Calcination
b) Roasting
c) Froth flotation
d) Electrolysis
Answer: b) Roasting
Explanation: After concentration, the ore is roasted to convert the metal into its oxide form, which can then be reduced to extract the metal.


32. Which of the following is the main impurity in the extraction of aluminum from its ore bauxite?

a) Iron
b) Silica
c) Copper
d) Zinc
Answer: b) Silica
Explanation: Silica (SiO₂) is the main impurity present in bauxite ore, which must be removed during the refining process.


33. Which of the following processes involves heating an ore in the absence of air?

a) Roasting
b) Calcination
c) Smelting
d) Leaching
Answer: b) Calcination
Explanation: Calcination involves heating an ore in the absence of air to remove volatile impurities and convert metal carbonates to oxides.


34. Which of the following methods is used for the extraction of metals like gold and silver?

a) Froth flotation
b) Leaching with cyanide
c) Electrolysis
d) Roasting
Answer: b) Leaching with cyanide
Explanation: Gold and silver are extracted using a cyanide solution in a process called cyanide leaching.


35. Which of the following is a characteristic of the Hall-Héroult process used for aluminum extraction?

a) Electrolysis of molten bauxite
b) Electrolysis of molten sodium chloride
c) Reduction with carbon
d) Heating in a furnace
Answer: a) Electrolysis of molten bauxite
Explanation: The Hall-Héroult process involves the electrolysis of molten bauxite (Al₂O₃) in the presence of cryolite to extract aluminum.


36. Which of the following metals is obtained from its ore by the process of electrolytic refining?

a) Copper
b) Zinc
c) Iron
d) Silver
Answer: a) Copper
Explanation: Copper is purified by electrolytic refining, where impure copper is made the anode and pure copper is deposited on the cathode.


37. Which of the following ores is used for the extraction of iron?

a) Bauxite
b) Galena
c) Haematite
d) Malachite
Answer: c) Haematite
Explanation: Haematite (Fe₂O₃) is the principal ore of iron used in its extraction.


38. Which of the following substances is used as a reducing agent in the extraction of metals?

a) Oxygen
b) Carbon
c) Nitrogen
d) Hydrogen
Answer: b) Carbon
Explanation: Carbon is commonly used as a reducing agent to reduce metal oxides to pure metals in the extraction process.


39. In the extraction of metals, the process of reducing a metal oxide by carbon is called:

a) Roasting
b) Reduction
c) Electrolysis
d) Leaching
Answer: b) Reduction
Explanation: Reduction is the process of extracting metals by removing oxygen from metal oxides, typically using carbon.


40. The process used for the extraction of zinc from its ore is:

a) Electrolysis
b) Froth flotation
c) Roasting and reduction
d) Hydrometallurgical process
Answer: c) Roasting and reduction
Explanation: Zinc is extracted by roasting zinc blende (ZnS) and reducing the resulting zinc oxide with carbon.


41. Which of the following is used in the extraction of gold from its ore?

a) Sodium hydroxide
b) Sodium cyanide
c) Sulfuric acid
d) Potassium chloride
Answer: b) Sodium cyanide
Explanation: Gold is extracted from its ore using sodium cyanide solution in the cyanide process.


42. Which of the following metals is obtained through the process of thermite reaction?

a) Magnesium
b) Aluminium
c) Copper
d) Iron
Answer: d) Iron
Explanation: Iron is extracted from its oxide using aluminium powder in a thermite reaction, producing molten iron.


43. Which of the following metals is obtained by the process of electrolysis of aqueous solutions?

a) Aluminium
b) Copper
c) Sodium
d) Potassium
Answer: b) Copper
Explanation: Copper is obtained by electrolytic refining in which impure copper is used as the anode and pure copper is deposited on the cathode.


44. Which of the following is true about the extraction of metals?

a) All metals can be extracted using carbon as a reducing agent.
b) Only metals with low reactivity can be extracted using carbon.
c) Metals like sodium and calcium are extracted by heating with carbon.
d) Electrolysis is used to extract metals with very low reactivity.
Answer: b) Only metals with low reactivity can be extracted using carbon.
Explanation: Carbon reduction is suitable for metals with low reactivity, while more reactive metals require electrolysis.


45. Which of the following is used for extracting aluminum from bauxite?

a) Roasting
b) Leaching
c) Electrolysis
d) Hydrogenation
Answer: c) Electrolysis
Explanation: Aluminum is extracted from bauxite using electrolysis, particularly the Hall-Héroult process.


46. The process of extracting iron from its ore in the blast furnace involves which of the following reactions?

a) Oxidation
b) Reduction
c) Addition
d) Substitution
Answer: b) Reduction
Explanation: In the blast furnace, iron ore (Fe₂O₃) is reduced by carbon monoxide to produce iron.


47. Which of the following metals is extracted by heating its ore with carbon in a blast furnace?

a) Gold
b) Zinc
c) Iron
d) Copper
Answer: c) Iron
Explanation: Iron is extracted from hematite ore in the blast furnace by reducing iron oxides with carbon.


48. Which of the following is the first step in the extraction of iron from its ore?

a) Reduction of iron oxide
b) Roasting of ore
c) Heating the ore in the furnace
d) Concentration of ore
Answer: d) Concentration of ore
Explanation: The first step in iron extraction is the concentration of the ore to remove impurities like sand and clay.


49. Which of the following methods is used for the extraction of alkali metals like sodium?

a) Electrolysis of molten salts
b) Roasting with carbon
c) Leaching with acids
d) Froth flotation
Answer: a) Electrolysis of molten salts
Explanation: Alkali metals like sodium are extracted by electrolysis of molten salts, such as sodium chloride.


50. Which of the following processes involves the separation of a metal from its ore by dissolving the metal in a suitable solvent?

a) Roasting
b) Amalgamation
c) Leaching
d) Electrolysis
Answer: c) Leaching
Explanation: Leaching involves dissolving a metal from its ore using a suitable solvent, such as cyanide for gold.