PYQ Vault

Day 213: CBSE Class 10 Science

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

  1. Question 1 (case study, 4 parts)

    Metals and Non-metals. Asked once: 2023 (same type asked 4 times)

    On the basis of reactivity metals are grouped into three categories – (i) Metals of low reactivity (ii) Metals of medium reactivity (iii) Metals of high reactivity Therefore metals are extracted in pure form from their ores on the basis of their chemical properties. Metals of high reactivity are extracted from their ores by electrolysis of the molten ore. Metals of low reactivity are extracted from their sulphide ores, which are converted into their oxides. The oxides of these metals are reduced to metals by simple heating.
    37 (a)
    Name the process of reduction used for a metal that gives vigorous reaction with air and water both.
    37 (b)
    Carbon cannot be used as a reducing agent to obtain aluminium from its oxide ? Why ?
    37 (c)
    Describe briefly the method to obtain mercury from cinnabar. Write the chemical equation for the reactions involved in the process.
    37 (c) OR
    Differentiate between roasting and calcination giving chemical equation for each.

  2. Question 2

    Metals and Non-metals. Asked once: 2023 (same type asked 4 times)

    Two statements are given, one labelled Assertion (A) and the other labelled Reason (R). Select the correct answer from the options given below.
    17
    Assertion (A) : The colour of aqueous solution of copper sulphate turns colourless when a piece of lead is added to it. Reason (R) : Lead is more reactive than copper, and hence displaces copper from its salt solution.

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  3. Question 3

    Our Environment. Asked once: 2024 (same type asked 4 times)

    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) : Accumulation of harmful chemicals is maximum in the organisms at the highest trophic level of a food chain. Reason (R) : Harmful chemicals are sprayed on the crops to protect them from diseases and pests.

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  4. Question 4

    Our Environment. Asked once: 2024 (same type asked 4 times)

    16
    Consider the following statements about ozone : (a) Ozone is poisonous gas. (b) Ozone shields the earth’s surface from the infrared radiation from the sun. (c) Ozone is a product of UV radiations acting on oxygen molecule. (d) At the lower level of the earth’s atmosphere, ozone performs most essential function. The correct statements are

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  5. Question 5

    The Human Eye and the Colourful World. Asked once: 2024 (same type asked 4 times)

    13
    The colour of light for which the refractive index of glass is minimum, is :

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