PYQ Vault

Day 166: CBSE Class 10 Science

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

  1. Question 1

    Our Environment. Asked once: 2023 (same type asked 3 times)

    10
    Choose the option giving correct matching the items given in Column – I & II.
    Column – IColumn – II
    A. Physical environment(i) Ozone layer depletion
    B. Exposure to UV radiation(ii) Bacteria and Fungi
    C. Chlorofluoro Carbon compounds(iii) Abiotic components
    D. Decomposers(iv) Skin Cancer

    Tap an option to check your answer.

  2. Question 2

    Our Environment. Asked once: 2024 (same type asked 3 times)

    33
    Study the picture given below showing three food chains (a), (b) and (c) and answer the following questions : (i) Name the type of ecosystems that exist in food chains (b) and (c). (ii) The first trophic level in all food chains are producers. Why ? What percentage of solar energy do these producers capture for their use ? (iii) Why are the arrows shown in the diagram in one direction only and not vice versa ? Justify.

  3. Question 3

    How do Organisms Reproduce?. Asked once: 2023 (same type asked 3 times)

    11
    The thread like structures that develop on a moist slice of bread in Rhizopus are

    Tap an option to check your answer.

  4. Question 4 (case study, 4 parts)

    Acids, Bases and Salts. Asked once: 2025 (same type asked 2 times)

    Seawater contains many salts dissolved in it. Common salt is separated from these salts. Deposits of solid salt are also found in several parts of the world. These large crystals are often brown due to impurities. This is called rock salt and is mined like coal. The common salt is an important raw material for chemicals of daily use.
    37 (a)
    Write balanced chemical equations to show the products formed during electrolysis of brine.
    37 (b)
    List two uses of any one product obtained during electrolysis of brine.
    37 (c) (i)
    A mild non-corrosive basic salt ‘A’, used for faster cooking, is strongly heated to produce a compound ‘B’, that is used for removing permanent hardness of water. Identify A and B and also write the equation for the reaction that occurs when A is heated.
    37 (c) (ii)
    Define water of crystallisation. Give two examples of salts that have water of crystallisation.

  5. Question 5

    Acids, Bases and Salts. Asked once: 2025 (same type asked 2 times)

    22
    A chemical compound ‘X’ is used to bleach washed clothes in laundry as well as to make drinking water free from germs. Identify ‘X’. How is this compound represented ? Write the method of its preparation along with the chemical equation for the reaction that occurs.