ICSE Class 10

General instructions: Answer all questions. Marks are shown in brackets [ ].

Objective

1. 1.
   The ore that can be concentrated by using magnetic separation:

   1. A. Corundum
   2. B. Hematite
   3. C. Calamine
   4. D. Bauxite
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2. 2.
   Why are metals good conductors of electricity?

   1. A. Metals have a high density which allows electricity to flow easily.
   2. B. Metals contain free-moving electrons that carry electric current.
   3. C. Metals form ionic bonds that facilitate the movement of protons.
   4. D. Metals have a rigid lattice structure that conducts electricity through vibrations.
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3. 3.
   Define the term 'metallurgy' and identify which of the following correctly represents the processes involved in metallurgy?

   1. A. Metallurgy is the study of metals and their properties, involving mining, melting, and shaping metals for use.
   2. B. Metallurgy is the science and technology of extracting metals from their ores, refining them, and preparing them for use, involving concentration of ore, reduction of ore, and refining of metal.
   3. C. Metallurgy refers to the process of creating alloys only, involving mixing, heating, and cooling metals.
   4. D. Metallurgy is the technique of polishing metals to improve their appearance, involving cleaning, buffing, and coating.
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4. 4.
   Which of the following is an ore of zinc containing its sulphide?

   1. A. Calamine
   2. B. Zinc blende
   3. C. Bauxite
   4. D. Hematite
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5. 5.
   What is galvanisation, and how does it protect iron from rusting?

   1. A. Galvanisation is the coating of iron with zinc to prevent rusting by forming a physical barrier against oxygen and moisture.
   2. B. Galvanisation is the process of coating iron with zinc, which protects iron through sacrificial protection by corroding in place of iron.
   3. C. Galvanisation involves painting iron with a protective layer that chemically neutralizes rust formation.
   4. D. Galvanisation is the application of a tin layer on iron, which reacts with oxygen to form a protective oxide layer.
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6. 6.
   Which alloy of lead and tin is commonly used in electrical circuits?

   1. A. Brass
   2. B. Solder
   3. C. Bronze
   4. D. Pewter
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7. 7.
   Identify the metallic oxide which is amphoteric in nature:

   1. A. Calcium oxide
   2. B. Zinc oxide
   3. C. Barium oxide
   4. D. Copper(II) oxide
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8. 8.
   State the three main objectives achieved during the roasting of ores. Which of the following correctly identifies one of these objectives?

   1. A. Removal of non-volatile impurities like silica and alumina from the ore.
   2. B. Conversion of sulphide ores to oxides, making them easier to reduce.
   3. C. Complete reduction of the ore to its pure metal form.
   4. D. Addition of carbon to the ore to facilitate smelting.
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9. 9.
   Describe the principle of extraction of metals from their compounds by reduction. Which of the following correctly illustrates this principle with appropriate examples?

   1. A. Metals are extracted by reduction using carbon (e.g., ZnO + C → Zn + CO) or electrolysis (e.g., Na from molten NaCl).
   2. B. Metals are extracted by oxidation using carbon (e.g., Zn + CO → ZnO + C) for all types of metals.
   3. C. Less reactive metals like sodium are extracted using carbon reduction, while highly reactive metals use electrolysis.
   4. D. Metals are extracted by heating their ores in air (e.g., Fe₂O₃ → Fe + O₂) without any reducing agent.
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10. 10.
    What is the process of roasting, and which of the following correctly represents the chemical equations for the roasting of zinc blende, galena, and iron pyrite?

    1. A. Heating the ore in the absence of air to remove volatile impurities; ZnS → Zn + S, PbS → Pb + S, FeS₂ → Fe + 2S
    2. B. Heating the ore in the presence of air to convert sulphide ores into oxides; 2ZnS + 3O₂ → 2ZnO + 2SO₂, 2PbS + 3O₂ → 2PbO + 2SO₂, 4FeS₂ + 11O₂ → 2Fe₂O₃ + 8SO₂
    3. C. Reducing the ore using carbon to extract the metal; ZnS + C → Zn + CS₂, PbS + C → Pb + CS₂, FeS₂ + 2C → Fe + 2CS₂
    4. D. Dissolving the ore in acid to form soluble salts; ZnS + 2HCl → ZnCl₂ + H₂S, PbS + 2HCl → PbCl₂ + H₂S, FeS₂ + 2HCl → FeCl₂ + H₂S + S
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11. 11.
    Which of the following equations correctly represents the burning of aluminium in air?

    1. A. 4Al + 3O₂ → 2Al₂O₃
    2. B. 2Al + N₂ → 2AlN
    3. C. 4Al + 3O₂ → 2Al₂O₃; 2Al + N₂ → 2AlN
    4. D. Al + O₂ → AlO₂
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12. 12.
    Which of the following sets of balanced equations correctly represents the reduction of the given metal oxides with the specified reducing agents? 1. Copper oxide with carbon. 2. Copper oxide with carbon monoxide. 3. Copper oxide with hydrogen. 4. Iron(II) oxide with carbon. 5. Lead oxide with hydrogen.

    1. A. 1. CuO + C → Cu + CO₂ 2. CuO + CO → Cu + CO 3. CuO + H₂ → Cu + H₂O 4. FeO + C → Fe + CO₂ 5. PbO + H₂ → Pb + H₂O
    2. B. 1. CuO + C → Cu + CO 2. CuO + CO → Cu + CO₂ 3. CuO + H₂ → Cu + H₂O 4. FeO + C → Fe + CO 5. PbO + H₂ → Pb + H₂O
    3. C. 1. CuO + C → Cu + CO 2. CuO + CO → Cu + CO 3. CuO + H₂ → Cu + H₂O₂ 4. FeO + C → Fe + CO₂ 5. PbO + H₂ → Pb + H₂O
    4. D. 1. CuO + C → Cu + CO₂ 2. CuO + CO → Cu + CO₂ 3. CuO + H₂ → Cu + H₂O 4. FeO + C → Fe + CO 5. PbO + H₂ → PbO + H₂O
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13. 13.
    Which equation correctly represents the reduction of zinc oxide?

    1. A. ZnO + C → Zn + CO₂
    2. B. ZnO + C → Zn + CO
    3. C. ZnO + H₂ → Zn + H₂O
    4. D. ZnO + O₂ → Zn + CO₂
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14. 14.
    Which of the following correctly represents the equations for the reaction of aluminium with dilute and concentrated sulphuric acid?

    1. A. Dilute: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂; Concentrated: 2Al + 6H₂SO₄ → Al₂(SO₄)₃ + 6H₂O + 3SO₂
    2. B. Dilute: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂O; Concentrated: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3SO₂
    3. C. Dilute: Al + H₂SO₄ → AlSO₄ + H₂; Concentrated: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂
    4. D. Dilute: 2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3SO₂; Concentrated: 2Al + 6H₂SO₄ → Al₂(SO₄)₃ + 6H₂O + 3H₂
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15. 15.
    (v) The main purpose of Roasting and Calcination is to convert

    1. A. ore into metal
    2. B. ore into metallic carbonate
    3. C. ore into oxide
    4. D. None of these
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16. 16.
    Which of the following sets of balanced equations correctly represents the reaction of the given metals with dilute hydrochloric acid? 1. Sodium 2. Calcium 3. Magnesium 4. Zinc 5. Iron 6. Lead

    1. A. 1. Na + HCl → NaCl + H₂ 2. Ca + HCl → CaCl₂ + H₂ 3. Mg + HCl → MgCl + H₂ 4. Zn + HCl → ZnCl₂ + H₂ 5. Fe + HCl → FeCl₂ + H₂ 6. Pb + 2HCl → PbCl₂ + H₂
    2. B. 1. 2Na + 2HCl → 2NaCl + H₂ 2. Ca + 2HCl → CaCl₂ + H₂ 3. Mg + 2HCl → MgCl₂ + H₂ 4. Zn + 2HCl → ZnCl₂ + H₂ 5. Fe + 2HCl → FeCl₂ + H₂ 6. Pb + 2HCl → PbCl₂ + H₂
    3. C. 1. Na + 2HCl → NaCl₂ + H₂ 2. Ca + HCl → CaCl + H₂ 3. 2Mg + 2HCl → 2MgCl + H₂ 4. Zn + HCl → ZnCl + H₂ 5. Fe + HCl → FeCl₃ + H₂ 6. Pb + HCl → PbCl + H₂
    4. D. 1. 2Na + HCl → Na₂Cl + H₂ 2. Ca + HCl → CaCl₂ + H₂ 3. Mg + HCl → MgCl₂ + H₂ 4. Zn + 2HCl → ZnCl₂ + H₂ 5. 2Fe + 6HCl → 2FeCl₃ + 3H₂ 6. Pb + HCl → PbCl₂ + H₂
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17. 17.
    Which of the following correctly represents the half-reactions occurring at the cathode and anode during the electrolysis of molten sodium chloride (NaCl)?

    1. A. At Cathode: Na⁺ + e⁻ → Na; At Anode: 2 Cl⁻ → Cl₂ + 2 e⁻
    2. B. At Cathode: Cl⁻ - e⁻ → Cl; At Anode: Na⁺ + e⁻ → Na
    3. C. At Cathode: Na → Na⁺ + e⁻; At Anode: Cl₂ + 2 e⁻ → 2 Cl⁻
    4. D. At Cathode: 2 Na⁺ + 2 e⁻ → 2 Na; At Anode: Cl⁻ → Cl + e⁻
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18. 18.
    Which pair of half-reactions correctly represents the processes occurring at the cathode and anode during the electrolysis of molten magnesium chloride (MgCl₂)?

    1. A. At Cathode: Mg²⁺ + 2 e⁻ → Mg; At Anode: 2 Cl⁻ - 2 e⁻ → Cl₂
    2. B. At Cathode: Mg → Mg²⁺ + 2 e⁻; At Anode: Cl₂ + 2 e⁻ → 2 Cl⁻
    3. C. At Cathode: 2 Cl⁻ - 2 e⁻ → Cl₂; At Anode: Mg²⁺ + 2 e⁻ → Mg
    4. D. At Cathode: Mg²⁺ → Mg + 2 e⁻; At Anode: 2 Cl⁻ → Cl₂ + 2 e⁻
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19. 19.
    Which of the following correctly represents the anode and cathode reactions during the refining of aluminium in Hoope's process?

    1. A. Anode: Al³⁺ + 3e⁻ → Al (pure); Cathode: Al - 3e⁻ → Al³⁺ (impure)
    2. B. Anode: Al - 3e⁻ → Al³⁺ (impure); Cathode: Al³⁺ + 3e⁻ → Al (pure)
    3. C. Anode: 2O²⁻ - 4e⁻ → O₂; Cathode: Al³⁺ + 3e⁻ → Al (pure)
    4. D. Anode: Al - 3e⁻ → Al³⁺ (pure); Cathode: Al³⁺ + 3e⁻ → Al (impure)
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20. 20.
    Describe the extraction of iron from haematite in a blast furnace, including the key reactions and the role of flux. Which of the following correctly summarizes the primary function of limestone in this process?

    1. A. It acts as a fuel to increase the furnace temperature.
    2. B. It decomposes to form carbon monoxide, which reduces haematite to iron.
    3. C. It reacts with silica impurities to form slag, removing them from the iron.
    4. D. It directly reduces haematite to iron by providing calcium ions.
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