PYQ Vault

Day 168: CBSE Class 10 Science

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

  1. Question 1

    Metals and Non-metals. Asked once: 2025 (same type asked 2 times)

    5
    Two metals zinc and tin are dissolved separately in definite proportions in molten copper (the primary metal) to obtain two different alloys respectively known as :

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  2. Question 2

    Acids, Bases and Salts. Asked once: 2024 (same type asked 2 times)

    5
    Consider the following compounds : FeSO4\mathrm{FeSO_4} ; CuSO4\mathrm{CuSO_4} ; CaSO4\mathrm{CaSO_4} ; Na2CO3\mathrm{Na_2CO_3} The compound having maximum number of water of crystallisation in its crystalline form in one molecule is :

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  3. Question 3

    Carbon and its Compounds. Asked once: 2023 (same type asked 2 times)

    34 (a)
    (i) A compound ‘A’ with a molecular formula of C2H4O2\mathrm{C_2H_4O_2} reacts with a base to give salt and water. Identify ‘A’, state its nature and the name of the functional group it possesses. Write chemical equation for the reaction involved. (ii) When the above stated compound ‘A’ reacts with another compound ‘B’ having molecular formula C2H6O\mathrm{C_2H_6O} in the presence of an acid, a sweet smelling compound ‘C’ is formed. (1) Identify ‘B’ and ‘C’. (2) State the role of acid in this reaction. (3) Write chemical equation for the reaction involved.

  4. Question 4

    Carbon and its Compounds. Asked once: 2023 (same type asked 2 times)

    34 (b)
    (i) What is a homologous series of carbon compounds ? Write general formula for alkynes. Name and draw the electron dot structure of first homologue of this series. (ii) State the meaning of the functional group in an organic compound. Write the formula of the functional group present in alcohols and carboxylic acids.

  5. Question 5

    Chemical Reactions and Equations. Asked once: 2024 (same type asked 2 times)

    34 (b)
    (i) Define a decomposition reaction. How can we say that (I) electrolysis of water, and (II) blackening of silver bromide when exposed to sunlight, are decomposition reactions ? Mention the type of energy involved in each case. (ii) “The type of reactions in which (I) calcium oxide is formed, and (II) calcium hydroxide is formed are opposite reactions to each other.” Justify this statement with the help of chemical equations.