ICSE Class 10

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

Objective

1. 1.
   How would you convert ethene into 1,2-dibromoethane?

   1. A. Pass ethene through bromine water to form 1,2-dibromoethane via addition.
   2. B. React ethene with hydrogen gas in the presence of a nickel catalyst.
   3. C. Treat ethene with chlorine water to produce 1,2-dibromoethane.
   4. D. Heat ethene with bromine in the absence of water to form bromoethane.
   [1]
2. 2.
   $\mathrm{C_3H_7}$ is named as ... radical.

   1. A. Alkyl
   2. B. Ethyl
   3. C. Propyl
   4. D. Butyl
   [1]
3. 3.
   Write the balanced chemical equation for the complete combustion of ethene. Which of the following correctly represents the products formed in this reaction?

   1. A. Carbon monoxide and hydrogen gas
   2. B. Carbon dioxide and water vapor
   3. C. Carbon and water vapor
   4. D. Methane and oxygen gas
   [1]
4. 4.
   Triple bond is present in

   1. a. Alkanes
   2. b. Alkenes
   3. c. Alkyls
   4. d. Alkynes
   [1]
5. 5.
   A carbon atom linked with two carbon atoms is known as ……… carbon.

   1. A. primary
   2. B. tertiary
   3. C. secondary
   4. D. chiral
   [1]
6. 6.
   Which hydrocarbon is primarily responsible for causing global warming?

   1. A. Ethane
   2. B. Methane
   3. C. Propane
   4. D. Butane
   [1]
7. 7.
   Acetylene polymerises into benzene by joining:

   1. A. 6 molecules
   2. B. 2 molecules
   3. C. 4 molecules
   4. D. 3 molecules
   [1]
8. 8.
   Which of the following correctly represents the general formula for paraffins, olefins, and alkynes?

   1. A. CₙH₂ₙ, CₙH₂ₙ₊₂, CₙH₂ₙ₋₂
   2. B. CₙH₂ₙ₊₂, CₙH₂ₙ, CₙH₂ₙ₋₂
   3. C. CₙH₂ₙ₋₂, CₙH₂ₙ, CₙH₂ₙ₊₂
   4. D. CₙH₂ₙ₊₂, CₙH₂ₙ₋₂, CₙH₂ₙ
   [1]
9. 9.
   Identify the statement that is incorrect about alkanes:

   1. a. They are hydrocarbons.
   2. b. There is a single covalent bond between carbon and hydrogen.
   3. c. They can undergo both substitution as well as addition reactions.
   4. d. On complete combustion they produce carbon dioxide and water.
   [1]
10. 10.
    Which of the following sets correctly represents the structural formulas for the position isomers of butyne (C₄H₆)?

    1. A. But-1-yne: CH₃—CH₂—C≡CH and But-2-yne: CH₃—C≡C—CH₃
    2. B. But-1-yne: CH₃—C≡C—CH₃ and But-2-yne: CH₃—CH₂—C≡CH
    3. C. But-1-yne: CH₃—CH=CH—CH₃ and But-2-yne: CH₃—C≡C—CH₃
    4. D. But-1-yne: CH₃—CH₂—CH=CH₂ and But-2-yne: CH₃—CH=CH—CH₃
    [1]
11. 11.
    Which balanced equation represents the formation of ethyl ethanoate from ethanoic acid?

    1. A. CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O (Conc. H₂SO₄)
    2. B. CH₃COOH + C₂H₅OH → C₂H₅COOH + CH₃OH
    3. C. 2CH₃COOH + C₂H₅OH → (CH₃COO)₂C₂H₅ + H₂O
    4. D. CH₃COOH + C₂H₅OH → CH₃COC₂H₅ + H₂O₂
    [1]
12. 12.
    Describe the laboratory preparation of methane by the reaction of aluminum carbide with water. Which of the following represents the correct balanced chemical equation for this reaction?

    1. A. Al₄C₃ + 6H₂O → 4Al(OH)₃ + 3CH₄
    2. B. Al₄C₃ + 12H₂O → 4Al(OH)₃ + 3CH₄
    3. C. Al₄C₃ + 3H₂O → 4Al(OH)₃ + 3CH₄
    4. D. Al₄C₃ + 12H₂O → 2Al₂O₃ + 3CH₄ + 6H₂O
    [1]
13. 13.
    Identify the IUPAC names of the following organic compounds based on their structural formulae: 1. H Cl H H H | | | | | H - C - C - C - C - C - H | | | | | H H Cl H H 2. H H H | | | H - C - C - C - OH | | H H

    1. A. 1. 2,3-Dichloropentane; 2. Propanol
    2. B. 1. 2,3-Dichloropentane; 2. Propanoic acid
    3. C. 1. 1,2-Dichloropentane; 2. Propanal
    4. D. 1. 3,4-Dichloropentane; 2. Propanoic acid
    [1]
14. 14.
    When testing ethane and ethene with alkaline potassium permanganate solution, which observation is correct?

    1. A. Ethane decolourizes the solution, ethene does not
    2. B. Ethene decolourizes the solution, ethane shows no change
    3. C. Both gases turn the solution green
    4. D. Ethane forms a brown precipitate, ethene does not
    [1]
15. 15.
    In the following reaction equation, identify the formula and name of substance B: C₂H₄ + B → (Alk. KMnO₄, 200°C) C₂H₆.

    1. A. O₂ (Oxygen)
    2. B. H₂ (Hydrogen)
    3. C. Cl₂ (Chlorine)
    4. D. H₂O (Water)
    [1]
16. 16.
    Which fully balanced equation represents the reaction when acetic acid is warmed with ethanol in the presence of concentrated sulphuric acid?

    1. A. $$\mathrm{CH_3COOH + C_2H_5OH \rightarrow CH_3COC_2H_5 + H_2O}$$
    2. B. $$\mathrm{CH_3COOH + C_2H_5OH \xrightarrow{Conc. H_2SO_4} CH_3COOC_2H_5 + H_2O}$$
    3. C. $$\mathrm{CH_3COOH + C_2H_5OH \rightarrow CH_3CH_2COOH + CH_3OH}$$
    4. D. $$\mathrm{2CH_3COOH + C_2H_5OH \rightarrow (CH_3COO)_2C_2H_5 + H_2O}$$
    [1]
17. 17.
    Which of the following correctly describes the Wurtz reaction for the preparation of ethane, including its chemical equation and limitations?

    1. A. The reaction couples methyl iodide using sodium in dry ether to form ethane: $$2\mathrm{CH_3I + 2Na \xrightarrow[dry]{ether} H_3C-CH_3 + 2NaI}$$. It cannot prepare methane or alkanes with an odd number of carbon atoms.
    2. B. The reaction involves the substitution of iodine in methyl iodide with sodium to form ethane: $$\mathrm{CH_3I + Na \rightarrow CH_4 + NaI}$$. It is limited to alkanes with an even number of carbon atoms.
    3. C. The reaction couples alkyl halides using sodium in water to form ethane: $$2\mathrm{CH_3Br + 2Na \rightarrow H_3C-CH_3 + 2NaBr}$$. It cannot prepare alkanes with fewer than three carbon atoms.
    4. D. The reaction involves the addition of sodium to methyl iodide to form ethane: $$\mathrm{CH_3I + 2Na \rightarrow CH_3-CH_3 + NaI}$$. It is suitable for preparing all alkanes, including methane.
    [1]
18. 18.
    Write the IUPAC name of the following compound: ``` Cl | CH3 - CH2 - C - CH2OH | CH3 ```

    1. A. 2-Chloro-2-methylbutan-1-ol
    2. B. 1-Chloro-2-methylbutan-2-ol
    3. C. 3-Chloro-2-methylbutan-1-ol
    4. D. 2-Chloro-3-methylbutan-1-ol
    [1]
19. 19.
    Describe the preparation of methane from aluminium carbide. Which of the following correctly represents the process and its balanced chemical equation?

    1. A. Aluminium carbide reacts with water at room temperature to produce methane and aluminium hydroxide: $$\mathrm{Al_4C_3 + 12H_2O \rightarrow 3CH_4 + 4Al(OH)_3}$$
    2. B. Aluminium carbide reacts with hydrochloric acid to produce methane and aluminium chloride: $$\mathrm{Al_4C_3 + 12HCl \rightarrow 3CH_4 + 4AlCl_3}$$
    3. C. Aluminium carbide decomposes on heating to produce methane and aluminium oxide: $$\mathrm{Al_4C_3 \rightarrow 3CH_4 + 2Al_2O_3}$$
    4. D. Aluminium carbide reacts with oxygen to produce methane and aluminium hydroxide: $$\mathrm{Al_4C_3 + 6O_2 \rightarrow 3CH_4 + 4Al(OH)_3}$$
    [1]
20. 20.
    A → K₂Cr₂O₇ B → [O] (Vigorous oxidation) CH₃COOH. Identify the reactant A

    1. A. Propyl alcohol
    2. B. Isopropyl alcohol
    3. C. Ethyl alcohol
    4. D. tert-pentyl alcohol
    [1]