Chemical Reactions and Equations

CBSE Class 10 · Science · 31 past questions

1. Q1 2026

   The gases evolved on heating lead (II) nitrate crystals are…

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2. Q2 2026

   Which of the following is an example of a displacement reaction ?

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3. Q3 2026

   In the following equation…

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4. Q4 2026

   2 g of green coloured crystals of ferrous sulphate are heated in a dry boiling tube. Name the type of…

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5. Q5 2026

   When ferrous sulphate crystals are heated in a test tube, we observe that…

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6. Q6 2026

   A student notices that her silver jewellery turned dull and had a grey-black coating over it after wearing…

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7. Q7 Sample paper 2026-27

   Chameleons contain crystals that reflect light and produce colour. Adjusting the spacing between these…

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8. Q8 Sample paper 2026-27

   A food label is given below. E304 and E307b are added to the flavoured biscuits.… (with a figure)

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9. Q9 Sample paper 2026-27

   Attempt either option A or B.…

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10. Q10 2025

    The correct balanced chemical equation showing exothermic reaction in which natural gas burns in air is…

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11. Q11 2025

    Consider the following chemical equation…

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12. Q12 2025

    Electrolysis of water is a decomposition reaction. The mass ratio ($M_H : M_O$) of hydrogen and oxygen gases…

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13. Q13 2025

    The products formed when Aluminium and Magnesium are burnt in the presence of air respectively are…

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14. Q14 2025

    The metals obtained from their molten chlorides by the process of electrolytic reduction are…

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15. Q15 2025

    For Questions number 17 to 20, two statements are given — one labelled as Assertion (A) and the other…

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16. Q16 2024

    Solid Calcium oxide reacts vigorously with water to form Calcium hydroxide accompanied by the liberation of…

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17. Q17 2024

    Select from the following a process in which a combination reaction is involved…

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18. Q18 2024

    Identify the correct statement about the following reaction…

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19. Q19 2024

    Identify the product 'X' obtained in the following chemical reaction…

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20. Q20 2024

    Consider the following Chemical equation…

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21. Q21 2024

    Which one of the following reactions is different from the remaining three ?

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22. Q22 2024

    When magnesium ribbon is burnt in air, an ash of white colour is produced. Write chemical equation for the…

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23. Q23 2024

    When 2 mL of sodium hydroxide solution is added to few pieces of granulated zinc in a test tube and then…

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24. Q24 2024

    Select from the following a decomposition reaction in which source of energy for decomposition is light…

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25. Q25 2024

    MnO$_2$ + 4HCl $\to$ MnCl$_2$ + 2H$_2$O + Cl$_2$…

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26. Q26 2024

    Name the type of chemical reaction in which calcium oxide reacts with water. Justify your answer by giving…

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27. Q27 2023

    When aqueous solutions of potassium iodide and lead nitrate are mixed, an insoluble substance separates out.…

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28. Q28 2023

    A metal ribbon 'X' burns in oxygen with a dazzling white flame forming a white ash 'Y'. The correct…

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29. Q29 2023

    Q. No. 17 to 20 are Assertion – Reasoning based questions. These consist of two statements – Assertion (A)…

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30. Q30 2023

    Which of the following is an example of endothermic process ?

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31. Q31 2023

    In order to balance the following chemical equation, the values of the coefficients x and y respectively are…

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