PYQ Vault

Day 63: CBSE Class 10 Science

5 questions (8 parts). Try each one first, then open its answer.

  1. Question 1

    Acids, Bases and Salts. This type asked 2 times: 2023, 2026. This one: 2026

    22
    The natural sources of oxalic acid, lactic acid and methanoic acid respectively are :

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  2. Question 2 (case study, 4 parts)

    Acids, Bases and Salts. This type asked 2 times: 2025, 2026. This one: 2026

    In the given diagram, when electricity is passed through an aqueous solution of a common salt, a substance ‘Z’ is produced, along with the evolution of gases ‘X’ and ‘Y’. When a burning matchstick is brought near the gas ‘Y’, it burns with a pop sound, whereas ‘X’ is used for disinfecting drinking water. When ‘X’ is passed through slaked lime, an insoluble substance ‘A’ is produced.
    28 (a)
    Write the names of the gases ‘X’ and ‘Y’.
    28 (b)
    Write the balanced chemical equation for the formation of substance ‘Z’.
    28 (c) (i)
    What happens : (I) If a drop of red litmus solution is added to the aqueous solution of substance ‘Z’ ? (II) If CO2\mathrm{CO_2} gas is passed through ammoniacal solution of aqueous NaCl\mathrm{NaCl} ?
    28 (c) (ii)
    Identify the substance ‘A’ and write the balanced chemical equation of the reaction which takes place in its preparation.

  3. Question 3

    Acids, Bases and Salts. This type asked 2 times: 2025, 2026. This one: 2026

    22
    Baking powder is a mixture of :

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  4. Question 4

    Acids, Bases and Salts. This type asked 2 times: 2025, 2026. This one: 2026

    25
    Write the balanced chemical equations involved in the preparation of (a) Bleaching powder (b) Baking soda

  5. Question 5

    Carbon and its Compounds. This type asked 2 times: 2025, 2026. This one: 2026

    21
    Which of the following will not undergo addition reaction ?

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