1. The process of extraction of metals from their ores is called:
a) Refining
b) Concentration
c) Metallurgy
d) Smelting
Answer: c) Metallurgy
Explanation: Metallurgy is the science and technology of extracting and refining metals from their ores.
2. Which of the following is a carbonate ore?
a) Bauxite
b) Calamine
c) Hematite
d) Magnetite
Answer: b) Calamine
Explanation: Calamine (ZnCO₃) is a carbonate ore of zinc.
3. The ore of aluminium is:
a) Hematite
b) Bauxite
c) Galena
d) Cinnabar
Answer: b) Bauxite
Explanation: Aluminium is extracted from bauxite (Al₂O₃·2H₂O).
4. Haematite is an ore of:
a) Copper
b) Zinc
c) Iron
d) Aluminium
Answer: c) Iron
Explanation: Haematite (Fe₂O₃) is a principal ore of iron.
5. Galena is the chief ore of:
a) Lead
b) Copper
c) Zinc
d) Silver
Answer: a) Lead
Explanation: Galena (PbS) is a sulphide ore of lead.
6. Froth flotation method is used for the concentration of:
a) Oxide ores
b) Sulphide ores
c) Carbonate ores
d) Nitrate ores
Answer: b) Sulphide ores
Explanation: Sulphide ores (like ZnS, PbS) are concentrated by froth flotation.
7. Which gas is used in froth flotation to create bubbles?
a) Oxygen
b) Carbon dioxide
c) Air
d) Hydrogen
Answer: c) Air
Explanation: Air is blown through the mixture to form froth that carries sulphide ore particles.
8. Magnetic separation is suitable for:
a) Ores of iron
b) Ores of aluminium
c) Ores of copper
d) Ores of silver
Answer: a) Ores of iron
Explanation: Magnetic ores like magnetite (Fe₃O₄) are concentrated by magnetic separation.
9. The process of removing gangue from ore is called:
a) Smelting
b) Roasting
c) Concentration
d) Refining
Answer: c) Concentration
Explanation: The gangue (earthy impurities) is removed by concentration methods.
10. Which ore is concentrated by leaching?
a) Haematite
b) Bauxite
c) Galena
d) Magnetite
Answer: b) Bauxite
Explanation: Bauxite is leached with sodium hydroxide in Bayer’s process.
11. The gangue present in bauxite ore is usually:
a) Fe₂O₃ and SiO₂
b) PbS and Cu₂S
c) ZnS and CaCO₃
d) MnO₂ and MgO
Answer: a) Fe₂O₃ and SiO₂
Explanation: Bauxite is often associated with ferric oxide and silica as impurities.
12. Which of the following is an ore of copper?
a) Chalcopyrite
b) Malachite
c) Cuprite
d) All of these
Answer: d) All of these
Explanation: Chalcopyrite (CuFeS₂), Malachite (CuCO₃·Cu(OH)₂), Cuprite (Cu₂O) are copper ores.
13. Which one is an ore of mercury?
a) Cinnabar
b) Malachite
c) Galena
d) Bauxite
Answer: a) Cinnabar
Explanation: Cinnabar (HgS) is the main ore of mercury.
14. Which process is used for the concentration of argentite (Ag₂S)?
a) Gravity separation
b) Froth flotation
c) Magnetic separation
d) Electrolysis
Answer: b) Froth flotation
Explanation: Argentite (sulphide ore of silver) is concentrated by froth flotation.
15. Cassiterite is the ore of:
a) Tin
b) Iron
c) Zinc
d) Copper
Answer: a) Tin
Explanation: Cassiterite (SnO₂) is the chief ore of tin.
16. Which is the gangue in Haematite?
a) SiO₂
b) Al₂O₃
c) CaCO₃
d) MgCO₃
Answer: a) SiO₂
Explanation: Silica is the main gangue in haematite.
17. The ore of zinc which is sulphide is:
a) Calamine
b) Zincite
c) Sphalerite
d) Smithsonite
Answer: c) Sphalerite
Explanation: Sphalerite (ZnS) is a sulphide ore of zinc.
18. Which one is an oxide ore?
a) Magnetite
b) Galena
c) Cinnabar
d) Chalcopyrite
Answer: a) Magnetite
Explanation: Magnetite (Fe₃O₄) is an oxide ore of iron.
19. The process of heating the ore in the absence of air is called:
a) Roasting
b) Calcination
c) Smelting
d) Refining
Answer: b) Calcination
Explanation: Calcination is heating in the absence of air to remove volatile impurities.
20. Which method is used to remove gangue from powdered ore using water flow?
a) Leaching
b) Hydraulic washing
c) Froth flotation
d) Roasting
Answer: b) Hydraulic washing
Explanation: Hydraulic washing separates lighter gangue particles from heavier ore by water.
21. Which is a sulphide ore of iron?
a) Haematite
b) Magnetite
c) Iron pyrite
d) Siderite
Answer: c) Iron pyrite
Explanation: Iron pyrite (FeS₂) is a sulphide ore of iron.
22. The ore of aluminium purified by Bayer’s process is:
a) Haematite
b) Bauxite
c) Galena
d) Magnetite
Answer: b) Bauxite
Explanation: Bayer’s process is used for refining bauxite to alumina.
23. Which metal is obtained from sphalerite?
a) Iron
b) Zinc
c) Lead
d) Copper
Answer: b) Zinc
Explanation: Sphalerite (ZnS) is the chief ore of zinc.
24. The separation of ore particles from gangue using difference in density is:
a) Roasting
b) Gravity separation
c) Leaching
d) Froth flotation
Answer: b) Gravity separation
Explanation: Gravity separation uses density differences.
25. Which of the following methods is used for gold concentration?
a) Froth flotation
b) Leaching with cyanide
c) Magnetic separation
d) Hydraulic washing only
Answer: b) Leaching with cyanide
Explanation: Gold and silver are extracted from ores by leaching with NaCN solution.
26. The process of heating an ore in excess of air is called:
a) Calcination
b) Roasting
c) Smelting
d) Refining
Answer: b) Roasting
Explanation: Roasting involves heating sulphide ores in excess of air to convert them into oxides.
27. Which of the following ores is concentrated by roasting?
a) Haematite
b) Galena
c) Bauxite
d) Siderite
Answer: b) Galena
Explanation: Galena (PbS) is roasted to PbO, which is then reduced.
28. In roasting, sulphide ores are converted into:
a) Sulphates
b) Oxides
c) Chlorides
d) Carbonates
Answer: b) Oxides
Explanation: Sulphide ores + O₂ → Metal oxides + SO₂.
29. The process used for carbonate ores is:
a) Roasting
b) Calcination
c) Smelting
d) Electrolysis
Answer: b) Calcination
Explanation: Carbonate ores (like CaCO₃, ZnCO₃) decompose to oxides and CO₂ on calcination.
30. Calcination of CaCO₃ gives:
a) CaO + CO₂
b) CaCO₃ + H₂O
c) Ca + O₂
d) Ca(OH)₂
Answer: a) CaO + CO₂
Explanation: On calcination, calcium carbonate decomposes to quicklime and CO₂.
31. Which ore is reduced by aluminothermic reduction?
a) MnO₂
b) ZnO
c) Cu₂O
d) CaO
Answer: a) MnO₂
Explanation: MnO₂ + Al → Mn + Al₂O₃ (exothermic thermite reaction).
32. The Ellingham diagram is used to predict:
a) Magnetic properties
b) Reduction feasibility
c) Melting points
d) Hardness
Answer: b) Reduction feasibility
Explanation: Ellingham diagram relates ΔG of oxide formation with temperature → helps in choosing reducing agents.
33. Which reducing agent is used in blast furnace for iron extraction?
a) H₂
b) C (coke)
c) Al
d) Na
Answer: b) C (coke)
Explanation: Coke acts as both fuel and reducing agent in blast furnace.
34. Smelting is:
a) Heating without air
b) Melting ore with reducing agent
c) Electrolytic refining
d) Removal of gangue
Answer: b) Melting ore with reducing agent
Explanation: Smelting extracts metals in molten state from their ores.
35. In metallurgy, flux is used to:
a) Reduce metal oxide
b) Remove impurities
c) Improve conductivity
d) Extract sulphur
Answer: b) Remove impurities
Explanation: Flux reacts with gangue → forms fusible slag.
36. The flux used for silica impurity is:
a) CaO
b) SiO₂
c) Na₂CO₃
d) MgO
Answer: a) CaO
Explanation: Acidic gangue (SiO₂) + basic flux (CaO) → CaSiO₃ (slag).
37. The main function of limestone in blast furnace is:
a) As a reducing agent
b) As a flux
c) To supply CO₂
d) To absorb heat
Answer: b) As a flux
Explanation: Limestone decomposes to CaO, which reacts with SiO₂ to form slag.
38. Which of the following is not a method of reduction?
a) Electrolytic reduction
b) Thermal reduction
c) Chemical reduction
d) Radioactive reduction
Answer: d) Radioactive reduction
Explanation: Metals are reduced by electrolytic, thermal, or chemical reduction but not by radioactive processes.
39. Which reducing agent is used in the extraction of tungsten?
a) C
b) H₂
c) Al
d) Na
Answer: b) H₂
Explanation: WO₃ + 3H₂ → W + 3H₂O. Hydrogen is used for reduction.
40. Which metal is extracted by electrolytic reduction of its molten salt?
a) Cu
b) Al
c) Fe
d) Zn
Answer: b) Al
Explanation: Aluminium is extracted from molten alumina (Hall-Héroult process).
41. Which metal is obtained by electrolytic reduction of cryolite mixture?
a) Fe
b) Al
c) Cu
d) Zn
Answer: b) Al
Explanation: Alumina dissolved in cryolite is electrolyzed to obtain aluminium.
42. The role of cryolite in aluminium extraction is:
a) Acts as flux
b) Lowers melting point of alumina
c) Increases conductivity
d) All of the above
Answer: d) All of the above
Explanation: Cryolite lowers melting point, increases conductivity, and acts as flux.
43. The anode used in Hall-Héroult process is made of:
a) Iron
b) Copper
c) Graphite
d) Aluminium
Answer: c) Graphite
Explanation: Graphite anode prevents contamination and conducts electricity.
44. Which gas is released at the anode in aluminium extraction?
a) O₂
b) CO₂
c) CO
d) H₂
Answer: b) CO₂
Explanation: O²⁻ ions discharge at anode → graphite anode oxidized → CO₂.
45. Which process is used for extraction of highly reactive metals like Na, K, Ca?
a) Smelting
b) Thermite reduction
c) Electrolytic reduction
d) Roasting
Answer: c) Electrolytic reduction
Explanation: Alkali and alkaline earth metals are extracted by electrolysis of their molten salts.
46. Which reducing agent is used for extraction of copper from Cu₂O?
a) C
b) Fe
c) CO
d) Cu
Answer: d) Cu
Explanation: Self-reduction: Cu₂O + Cu₂S → Cu + SO₂.
47. Which process is used for the extraction of Zn from ZnO?
a) Reduction with C
b) Electrolysis
c) Reduction with H₂
d) Reduction with Al
Answer: a) Reduction with C
Explanation: ZnO + C → Zn + CO.
48. Which is reduced in blast furnace during Fe extraction?
a) Fe₂O₃
b) Fe₃O₄
c) FeO
d) All of these
Answer: d) All of these
Explanation: In blast furnace, Fe₂O₃ → Fe₃O₄ → FeO → Fe (stepwise reduction).
49. The chief reducing agent in blast furnace is:
a) C
b) CO
c) H₂
d) Al
Answer: b) CO
Explanation: CO formed inside the furnace reduces Fe oxides to metallic Fe.
50. The slag formed in blast furnace is:
a) FeSiO₃
b) CaSiO₃
c) Al₂O₃
d) MgO
Answer: b) CaSiO₃
Explanation: Slag = CaO (from limestone) + SiO₂ (gangue) → CaSiO₃.
51. The process of purifying impure metals is called:
a) Smelting
b) Refining
c) Roasting
d) Calcination
Answer: b) Refining
Explanation: Refining removes impurities from a metal to obtain pure metal.
52. Electrolytic refining is suitable for metals:
a) Highly reactive
b) Less reactive
c) Only non-metals
d) Only alloys
Answer: b) Less reactive
Explanation: Metals like Cu, Ag, Zn, and Au are purified by electrolytic refining.
53. In electrolytic refining, the impure metal is made the:
a) Cathode
b) Anode
c) Electrolyte
d) Flux
Answer: b) Anode
Explanation: Impure metal is the anode; pure metal is deposited at cathode.
54. The electrolyte in copper refining is:
a) CuSO₄ + H₂SO₄ solution
b) NaCl solution
c) ZnSO₄ solution
d) KOH solution
Answer: a) CuSO₄ + H₂SO₄ solution
Explanation: Electrolyte contains Cu²⁺ ions for deposition of copper.
55. Which of the following metals is refined by the Mond process?
a) Ni
b) Cu
c) Zn
d) Al
Answer: a) Ni
Explanation: Nickel reacts with CO to form volatile Ni(CO)₄ → decomposed to pure Ni.
56. What is the cathode reaction in electrolytic refining of copper?
a) Cu²⁺ + 2e⁻ → Cu
b) Cu → Cu²⁺ + 2e⁻
c) Cu²⁺ → Cu⁺
d) Cu → Cu²⁺
Answer: a) Cu²⁺ + 2e⁻ → Cu
Explanation: Cu²⁺ ions gain electrons at cathode → pure copper deposited.
57. Which refining method uses selective oxidation?
a) Electrolytic refining
b) Hydrometallurgy
c) Poling method
d) Zone refining
Answer: c) Poling method
Explanation: Poling involves blowing greenwood over molten impure copper to remove oxygen and impurities.
58. Zone refining is used to purify:
a) Metals with high melting points
b) Metals with low melting points
c) Semiconductors like Si and Ge
d) All metals
Answer: c) Semiconductors like Si and Ge
Explanation: Zone refining removes trace impurities from semiconductors.
59. Cupellation is used to refine:
a) Silver
b) Copper
c) Zinc
d) Aluminium
Answer: a) Silver
Explanation: Impure silver is heated with PbO → impurities oxidized → pure silver left.
60. Which alloy contains copper and tin?
a) Brass
b) Bronze
c) Steel
d) Amalgam
Answer: b) Bronze
Explanation: Bronze = Cu + Sn, used for statues, coins, and tools.
61. Brass is an alloy of:
a) Cu + Zn
b) Cu + Sn
c) Fe + C
d) Al + Cu
Answer: a) Cu + Zn
Explanation: Brass = copper + zinc, used in musical instruments, coins.
62. Solder is an alloy of:
a) Sn + Pb
b) Cu + Zn
c) Cu + Sn
d) Al + Mg
Answer: a) Sn + Pb
Explanation: Solder melts easily → joins metal parts.
63. Duralumin is an alloy of:
a) Al + Cu
b) Al + Mg
c) Fe + C
d) Cu + Zn
Answer: a) Al + Cu
Explanation: Duralumin is lightweight, strong → used in aircraft.
64. Stainless steel is resistant to corrosion due to:
a) Nickel content
b) Chromium content
c) Copper content
d) Zinc content
Answer: b) Chromium content
Explanation: Cr forms a passive oxide layer preventing rust.
65. Which metal is refined by liquation?
a) Tin
b) Lead
c) Zinc
d) Copper
Answer: b) Lead
Explanation: Lead is purified by melting with salt → impurities float.
66. An amalgam is an alloy of:
a) Mercury + metal
b) Copper + Tin
c) Iron + Carbon
d) Zinc + Copper
Answer: a) Mercury + metal
Explanation: Dental fillings often use amalgams.
67. Aluminium is refined by:
a) Hall-Héroult process
b) Mond process
c) Electrolytic refining
d) Poling method
Answer: a) Hall-Héroult process
Explanation: Alumina is electrolyzed in molten cryolite to give aluminium.
68. Gold can be refined by:
a) Aqua regia
b) Electrolytic refining
c) Both a and b
d) Roasting
Answer: c) Both a and b
Explanation: Gold dissolves in aqua regia (HCl + HNO₃) → pure Au precipitated; also refined electrolytically.
69. The process of purifying metals by passing current through molten salt:
a) Electrolytic refining
b) Poling
c) Cupellation
d) Distillation
Answer: a) Electrolytic refining
Explanation: Metals like Cu, Zn, Ni are purified by electrolysis.
70. Aluminium alloys are mainly used for:
a) Coins
b) Aircraft and rockets
c) Jewellery
d) Solder
Answer: b) Aircraft and rockets
Explanation: Aluminium alloys = lightweight + strong → aerospace applications.
71. Which alloy is used for making coins?
a) Brass
b) Bronze
c) Nickel-Copper alloy
d) Duralumin
Answer: c) Nickel-Copper alloy
Explanation: Durable and resistant to corrosion → coins.
72. Type of steel used for cutting tools:
a) Stainless steel
b) High carbon steel
c) Mild steel
d) Brass
Answer: b) High carbon steel
Explanation: High C content → hard, strong → suitable for cutting.
73. Alloys of iron with carbon are called:
a) Steel
b) Bronze
c) Brass
d) Duralumin
Answer: a) Steel
Explanation: Steel = Fe + C (0.2–2%) → mechanical strength enhanced.
74. The main purpose of adding Cr in steel:
a) Increase toughness
b) Prevent corrosion
c) Increase ductility
d) Reduce cost
Answer: b) Prevent corrosion
Explanation: Cr forms Cr₂O₃ layer → stainless steel resists rust.
75. Nichrome is an alloy of:
a) Nickel + Chromium
b) Nickel + Copper
c) Iron + Chromium
d) Iron + Nickel
Answer: a) Nickel + Chromium
Explanation: Nichrome is used in heating elements due to high resistance and stability.
76. Which method is used for the extraction of highly reactive metals like K, Na, and Ca?
a) Smelting
b) Electrolytic reduction of molten salts
c) Roasting
d) Poling
Answer: b) Electrolytic reduction of molten salts
Explanation: Reactive metals cannot be reduced chemically → extracted via electrolysis.
77. Thermite process is mainly used for extraction of:
a) Aluminium
b) Iron
c) Copper
d) Zinc
Answer: b) Iron
Explanation: Al reduces Fe₂O₃ → Fe + Al₂O₃ (exothermic reaction).
78. Which method is used for extracting metals like Ti, Zr, and U?
a) Electrolytic reduction
b) Kroll process
c) Mond process
d) Poling
Answer: b) Kroll process
Explanation: TiCl₄ or ZrCl₄ is reduced with Mg → pure metal.
79. Which metal is extracted by Mond process?
a) Copper
b) Nickel
c) Zinc
d) Aluminium
Answer: b) Nickel
Explanation: Ni + CO → Ni(CO)₄ (volatile) → decomposed to Ni.
80. Which metal is obtained by electrolysis of fused cryolite?
a) Copper
b) Aluminium
c) Zinc
d) Iron
Answer: b) Aluminium
Explanation: Aluminium is extracted from alumina dissolved in molten cryolite (Hall-Héroult process).
81. Corrosion is:
a) Formation of alloys
b) Oxidation of metals to stable oxides
c) Reduction of metal ions
d) Melting of metals
Answer: b) Oxidation of metals to stable oxides
Explanation: Corrosion is the slow deterioration of metals due to chemical reactions.
82. Rusting occurs mainly in:
a) Copper
b) Iron
c) Aluminium
d) Zinc
Answer: b) Iron
Explanation: Iron + O₂ + H₂O → Fe₂O₃·xH₂O (rust).
83. The main component of rust is:
a) FeO
b) Fe₂O₃·xH₂O
c) Fe₃O₄
d) Fe(OH)₂
Answer: b) Fe₂O₃·xH₂O
Explanation: Rust is hydrated ferric oxide.
84. Which of the following prevents rusting by sacrificial protection?
a) Zinc coating
b) Paint
c) Alloying
d) Oil coating
Answer: a) Zinc coating
Explanation: Zinc corrodes preferentially → protects iron (galvanization).
85. Alluminium is resistant to corrosion due to:
a) Oxide layer formation
b) Alloying
c) Painting
d) Zinc coating
Answer: a) Oxide layer formation
Explanation: Al forms a thin protective Al₂O₃ layer → prevents further corrosion.
86. Which of the following methods is used to prevent rusting of iron?
a) Painting
b) Oiling
c) Galvanization
d) All of the above
Answer: d) All of the above
Explanation: Rusting can be prevented by coatings, oiling, or sacrificial metal protection.
87. Which metal is used in sacrificial anode method?
a) Aluminium
b) Zinc
c) Copper
d) Iron
Answer: b) Zinc
Explanation: Zinc corrodes instead of iron → iron remains protected.
88. Which of the following is a naturally occurring alloy?
a) Steel
b) Brass
c) Electrum
d) Duralumin
Answer: c) Electrum
Explanation: Electrum = natural alloy of gold and silver.
89. Bronze is an alloy of:
a) Cu + Sn
b) Cu + Zn
c) Fe + C
d) Al + Cu
Answer: a) Cu + Sn
Explanation: Bronze is used for statues, coins, and bearings.
90. Which of the following is used for making electrical wires?
a) Aluminium
b) Copper
c) Zinc
d) Lead
Answer: b) Copper
Explanation: High conductivity and ductility → electrical applications.
91. Which metal is used in thermocouples?
a) Iron
b) Copper
c) Nickel
d) Aluminium
Answer: c) Nickel
Explanation: Nickel alloys are used in thermocouples due to stable emf generation.
92. Stainless steel contains:
a) Iron + Nickel + Chromium
b) Iron + Tin
c) Iron + Carbon only
d) Iron + Copper
Answer: a) Iron + Nickel + Chromium
Explanation: Chromium → corrosion resistance; Nickel → toughness.
93. Nichrome is an alloy of:
a) Nickel + Chromium
b) Nickel + Copper
c) Iron + Chromium
d) Copper + Zinc
Answer: a) Nickel + Chromium
Explanation: Used in heating elements → high resistivity + corrosion resistance.
94. Which metal is used in aircraft manufacturing?
a) Aluminium
b) Copper
c) Zinc
d) Lead
Answer: a) Aluminium
Explanation: Lightweight and strong → aerospace industry.
95. Which of the following prevents oxidation of metals?
a) Alloying
b) Painting
c) Oiling
d) All of the above
Answer: d) All of the above
Explanation: Coatings and alloying prevent direct contact with air/water.
96. Gold is used in jewellery because:
a) High melting point
b) Resistance to corrosion
c) Easy to alloy
d) All of the above
Answer: d) All of the above
Explanation: Gold is malleable, ductile, and resistant → ideal for ornaments.
97. Which of the following metals is extracted by self-reduction method?
a) Copper
b) Aluminium
c) Zinc
d) Iron
Answer: a) Copper
Explanation: Cu₂O + Cu₂S → Cu + SO₂.
98. The main application of aluminium alloys:
a) Aircraft
b) Coins
c) Electrical wiring
d) Cutlery
Answer: a) Aircraft
Explanation: High strength-to-weight ratio → aerospace applications.
99. Which metal forms a protective oxide layer naturally?
a) Iron
b) Aluminium
c) Zinc
d) Lead
Answer: b) Aluminium
Explanation: Al₂O₃ layer protects aluminium from corrosion.
100. Which method is used to prevent electrolytic corrosion?
a) Sacrificial anode
b) Coating
c) Cathodic protection
d) All of the above
Answer: d) All of the above
Explanation: Electrolytic corrosion can be prevented by coating, sacrificial anode, or cathodic protection.