PYQ Vault

Day 25: CBSE Class 10 Science

5 questions. Try each one first, then open its answer.

  1. Question 1

    The Human Eye and the Colourful World. Asked 2 times: 2025*, 2026 (* = numbers or wording changed that year)

    31
    To restore clear vision in persons whose size of the eye ball has reduced, he/she is suggested to use suitable

    Tap an option to check your answer.

  2. Question 2

    How do Organisms Reproduce?. Asked 2 times: 2023*, 2026 (* = numbers or wording changed that year)

    11
    Do all variations in a species have equal chances of surviving in the environment in which they find themselves ? Explain.

  3. Question 3

    Acids, Bases and Salts. Asked 2 times: 2023*, 2025 (* = numbers or wording changed that year)

    4
    A metal, ‘X’, on treatment with sodium hydroxide liberates a gas ‘G’. It also liberates the same gas, ‘G’ on treatment with dilute sulphuric acid. Based on above information, ‘X’ and ‘G’ respectively are

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  4. Question 4

    Acids, Bases and Salts. Asked 2 times: 2024*, 2025 (* = numbers or wording changed that year)

    5
    Tooth enamel is made up of calcium hydroxyapatite (a crystalline form of calcium phosphate). This chemical starts corroding in the mouth when the pH is :

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  5. Question 5

    Acids, Bases and Salts. Asked 2 times: 2023*, 2025 (* = numbers or wording changed that year)

    Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
    18
    Assertion (A) : Concentrated nitric acid is diluted by adding water slowly to acid with constant stirring. Reason (R) : Concentrated nitric acid is easily soluble in water.

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