Practice test

Chemical changes and reactions - Test Set 1

Review 20 exam-focused questions with detailed explanations, then start the interactive test when you are ready.

20 questions

Questions and explanations

  1. Question 1

    Change of water into vapour is called:
    1. Physical
    2. Natural
    3. Chemical
    4. Biological
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  2. Question 2

    Assertion (A): A chemical reaction becomes faster at a higher temperature.
    Reason (R): At higher temperature, molecular motion becomes more rapid.
    1. Both (A) and (R) are true, and (R) is the correct explanation of (A).
    2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    3. (A) is true, but (R) is false.
    4. (A) is false, but (R) is true.
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  3. Question 3

    What form of energy is produced in the decomposition of water?
    1. Light
    2. Sound
    3. Heat
    4. Acid
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  4. Question 4

    Which of the following is not correctly matched?
    1. Desalination - Sea water
    2. Reverse osmosis - Potable water
    3. Denaturation - Proteins
    4. Pasteurization - Tea
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  5. Question 5

    By which process can seawater be converted into pure water?
    1. Reverse osmosis
    2. Deliquescence
    3. Efflorescence
    4. Electric separation
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  6. Question 6

    Who developed the theory of combustion as a chemical reaction with oxygen in the 18th century, that excluded phlogiston theory?
    1. Antoine Lavoisier
    2. Robert Boyle
    3. Friedrich Wohler
    4. Johann Becher
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  7. Question 7

    What is the chemical reaction that occurs when sugar is heated and turns into a caramel syrup?
    1. Caramelisation
    2. Maillard reaction
    3. Neutralisation
    4. Precipitation
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  8. Question 8

    What is the product formed when Zinc and Sulphuric acid react?
    1. Zinc sulphide
    2. Zinc oxide
    3. Zinc hydroxide
    4. Zinc sulphate
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  9. Question 9

    What is the gas evolved when Zinc reacts with Sulphuric acid?
    1. Carbon dioxide
    2. Hydrogen
    3. Oxygen
    4. Hydrogen sulphide
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  10. Question 10

    When Electricity is passed through Water, what kind of chemical reaction occurs?
    1. Displacement
    2. Combination
    3. Double displacement
    4. Decomposition
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  11. Question 11

    For a chemical reaction with a rise in temperature by 100, the rate constant becomes nearly ___________ .
    1. triple
    2. double
    3. half
    4. one-fourth
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  12. Question 12

    When an iron nail is dipped into a _________ coloured copper sulphate solution, its colour changes to ________ .
    1. blue, green
    2. green, blue
    3. blue, yellow
    4. yellow, blue
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  13. Question 13

    Which of the following is correctly paired?
    1. Cyanide ion - CN-
    2. Ammonia - OH-
    3. Bromide ion - F-
    4. Fluoride ion - Cl-
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  14. Question 14

    Due to which of the following reactions are household bleaching agents using phosphorous, sulphur and chlorine formed?
    1. Decomposition reaction
    2. Displacement reaction
    3. Combination reaction
    4. Disproportionation reaction
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  15. Question 15

    Which one among the following is an example of endothermic process?
    1. Combustion of carbon
    2. Mixing acid and alkali
    3. Photosynthesis
    4. Respiration
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  16. Question 16

    Which one of the following is NOT an oxidation reaction?
    1. Rusting of iron
    2. Opening of soda bottle
    3. Rancidity
    4. Combustion
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  17. Question 17

    Consider the following statements regarding burning of magnesium ribbon in air:
    1. White powder of MgO is formed.
    2. It is an example of combustion reaction.
    3. Heat and light are produced.
    Which of the statements given above are correct?
    1. 1 and 2 only
    2. 1 and 3 only
    3. 2 and 3 only
    4. 1, 2, and 3
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  18. Question 18

    What is the colour of the precipitate obtained by passing CO2 gas through lime water?
    1. Green
    2. Blue
    3. White
    4. Brown
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  19. Question 19

    Which of the following is/are the example(s) of Chemical change?
    1. Crystallization of Sodium chloride.
    2. Melting of ice
    3. Souring of Milk
    Select the Correct answer using the Code given below:
    1. 1 and 2 only
    2. 3 only
    3. 1, 2 and 3
    4. None of the above
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  20. Question 20

    Fruits stored in a cold chamber exhibit longer storage life because
    1. Exposure to sunlight is prevented
    2. Concentration of carbon dioxide in the environment is increased
    3. Rate of respiration is decreased
    4. There is an increase in humidity
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