ICSE Class 10

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

Objective

1. 1.
   Hydracids are those acids which contain

   1. a. hydrogen with any metal
   2. b. hydrogen, a non-metal and oxygen
   3. c. hydrogen and a non-metal other than oxygen
   4. d. hydrogen and oxygen only
   [1]
2. 2.
   What is a neutralization reaction? Provide an example to illustrate your answer.

   1. A. A reaction between an acid and a base to form salt and water, e.g., NaOH + HCl → NaCl + H₂O.
   2. B. A reaction where an acid reacts with a metal to produce hydrogen gas, e.g., Zn + H₂SO₄ → ZnSO₄ + H₂.
   3. C. A reaction between two acids to form a stronger acid and water, e.g., HCl + HNO₃ → H₂ClNO₃.
   4. D. A reaction where a base reacts with water to form a salt and oxygen, e.g., Ca(OH)₂ + H₂O → CaO + O₂.
   [1]
3. 3.
   Which gas is evolved when dilute MgSO₄ react with active metals such as Mg?

   1. A. SO₂
   2. B. CO₂
   3. C. H₂
   4. D. H₂S
   [1]
4. 4.
   Fill in the blank from the choices given: The basicity of acetic acid is ... [3, 1, 4].

   1. A. 3
   2. B. 1
   3. C. 4
   [1]
5. 5.
   Identify the base from the following options that is NOT classified as an alkali.

   1. A. Sodium hydroxide, NaOH
   2. B. Potassium hydroxide, KOH
   3. C. Zinc hydroxide, Zn(OH)₂
   4. D. Calcium hydroxide, Ca(OH)₂
   [1]
6. 6.
   Blue litmus paper when dipped in dil. HCl changes to which colour, and when dipped in dil. NaOH changes to which colour?

   1. A. changed red to blue
   2. B. changed blue to red
   3. C. remained blue
   4. D. changed first to red and then to blue
   [1]
7. 7.
   The acid anhydride of sulphuric acid is

   1. A. sulphur dioxide
   2. B. sulphur trioxide
   3. C. sulphur monochloride
   4. D. None of these
   [1]
8. 8.
   Which method describes the preparation of soluble salts by the action of alkalis on certain metals, their oxides, or hydroxides, and includes an example of the reaction?

   1. A. Reacting amphoteric metals like aluminium with sodium hydroxide to form sodium aluminate and hydrogen gas.
   2. B. Dissolving metals like copper in hydrochloric acid to form soluble copper chloride salts.
   3. C. Heating metal carbonates to produce soluble salts and carbon dioxide gas.
   4. D. Mixing alkalis with non-metals like sulfur to form soluble sulfates.
   [1]
9. 9.
   Which of the following correctly describes the precipitation method for preparing insoluble salts and provides a valid example?

   1. A. Insoluble salts are prepared by reacting two soluble salts or a soluble salt with an acid, forming a precipitate. Example: BaSO₄ from BaCl₂ and H₂SO₄.
   2. B. Insoluble salts are formed by heating a single soluble salt until it decomposes. Example: CaCO₃ from heating Ca(HCO₃)₂.
   3. C. Insoluble salts are obtained by evaporating a solution of a soluble salt. Example: NaCl from seawater evaporation.
   4. D. Insoluble salts are prepared by reacting a metal with an acid. Example: ZnSO₄ from Zn and H₂SO₄.
   [1]
10. 10.
    Which of the following represents the balanced chemical equation for the preparation of Iron (III) chloride (Ferric chloride)?

    1. A. Fe + Cl₂ → FeCl₂ (heated dry)
    2. B. 2 Fe + 3 Cl₂ → 2 FeCl₃ (heated dry)
    3. C. Fe + 3 Cl → FeCl₃ (heated dry)
    4. D. 2 Fe + Cl₂ → 2 FeCl (heated dry)
    [1]
11. 11.
    The acid which directly converts phosphorus to phosphoric acid is

    1. A. Dilute sulphuric acid
    2. B. Dilute acetic acid
    3. C. Dilute nitric acid
    4. D. Concentrated nitric acid
    [1]
12. 12.
    Which balanced chemical equation correctly represents the reaction between an acid and a sulphite to produce a salt, water, and sulphur dioxide?

    1. A. 2HCl + CaSO₃ → CaCl₂ + H₂O + SO₂↑
    2. B. HCl + CaSO₃ → CaCl₂ + H₂SO₃
    3. C. H₂SO₄ + CaSO₃ → CaSO₄ + H₂O + SO₃↑
    4. D. HNO₃ + CaSO₃ → Ca(NO₃)₂ + H₂O + SO₂↑
    [1]
13. 13.
    Why zinc chloride is stored in air-tight bottles ?

    1. A. Because it is highly basic substance.
    2. B. Because it is highly reactive substance.
    3. C. Because it is highly acidic substance.
    4. D. Because it is a deliquescent substance.
    [1]
14. 14.
    Carbonic acid is a dibasic acid. Why?

    1. A. Because it has double electron at its valence cell
    2. B. Because it has two replaceable hydrogen atoms
    3. C. Both (a) and (b) are correct
    4. D. None of the above
    [1]
15. 15.
    NaHSO₃ is an example of which type of salts?

    1. A. Complex salts
    2. B. Basic salts
    3. C. Normal salts
    4. D. Acidic salts
    [1]
16. 16.
    Choose the most appropriate answer from the following list of oxides which fit the description. Each answer may be used only once: [SO₂

    1. A. SO₂
    2. B. SiO₂
    3. C. Al₂O₃
    4. D. MgO
    5. E. CO
    6. F. Na₂O
    [2]
17. 17.
    Write the ionisation steps for sulphuric acid (H₂SO₄) in water and explain which of the following correctly describes how it forms acid salts and normal salts?

    1. A. H₂SO₄ ionises in one step: H₂SO₄ + 2H₂O → 2H₃O⁺ + SO₄²⁻, forming only normal salts like Na₂SO₄.
    2. B. H₂SO₄ ionises in two steps: first to H₃O⁺ + HSO₄⁻, then HSO₄⁻ to H₃O⁺ + SO₄²⁻, forming acid salts like NaHSO₄ and normal salts like Na₂SO₄.
    3. C. H₂SO₄ ionises in two steps but forms only acid salts like NaHSO₄, as both hydrogens are never fully replaced.
    4. D. H₂SO₄ ionises in one step: H₂SO₄ → 2H⁺ + SO₄²⁻, forming normal salts like NaHSO₄ when one hydrogen is replaced.
    [1]
18. 18.
    Which base reacts with hydrochloric acid to form a salt that, upon hydrolysis, yields a slightly acidic solution?

    1. A. Sodium hydroxide
    2. B. Potassium hydroxide
    3. C. Copper hydroxide
    4. D. Ammonium hydroxide
    [1]
19. 19.
    Why is anhydrous hydrogen chloride not an acid, while its aqueous solution is a strong acid?

    1. A. Anhydrous HCl is ionic, while aqueous HCl is covalent.
    2. B. Anhydrous HCl does not ionize; aqueous HCl ionizes to produce H₃O⁺ ions.
    3. C. Anhydrous HCl is a gas, while aqueous HCl is a liquid.
    4. D. Anhydrous HCl is unstable, while aqueous HCl is stable.
    [1]
20. 20.
    Nitrogen dioxide is described as a double acid anhydride. Why is this classification accurate?

    1. A. It reacts with water to form both nitric acid (HNO₃) and nitrous acid (HNO₂).
    2. B. It decomposes into nitrogen and oxygen when heated, releasing acidic gases.
    3. C. It forms only nitric acid (HNO₃) when dissolved in water.
    4. D. It neutralizes bases to produce a single acidic salt and water.
    [1]