PYQ Vault

Day 87: CBSE Class 10 Science

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

  1. Question 1

    Chemical Reactions and Equations. Asked once: 2025 (same type asked 3 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) : All exothermic reactions are accompanied with evolution of heat and light. Reason (R) : Combination reactions may or may not be exothermic.

    Tap an option to check your answer.

  2. Question 2

    Chemical Reactions and Equations. Asked once: 2026 (same type asked 3 times)

    27
    Answer the following : (a) Write two observations when green coloured crystals of ferrous sulphate are heated in a boiling tube. (b) Why brown coloured copper powder turns black on heating ? (c) What happens when limestone is heated strongly ?

  3. Question 3

    Chemical Reactions and Equations. Asked once: 2026 (same type asked 3 times)

    17
    Which of the following are combination reactions ? (i) 2KClO3⟶2KCl+3O2\mathrm{2KClO_3 \longrightarrow 2KCl + 3O_2} (ii) MgO+H2O⟶Mg(OH)2\mathrm{MgO + H_2O \longrightarrow Mg(OH)_2} (iii) 4Al+3O2⟶2Al2O3\mathrm{4Al + 3O_2 \longrightarrow 2Al_2O_3} (iv) Zn+FeSO4⟶ZnSO4+Fe\mathrm{Zn + FeSO_4 \longrightarrow ZnSO_4 + Fe}

    Tap an option to check your answer.

  4. Question 4

    Chemical Reactions and Equations. Asked once: 2025 (same type asked 3 times)

    21
    (a) In common practice silver is recovered from silver nitrate solution by the use of copper metal. Name the type of reaction that takes place in this process and give the chemical equation of the reaction involved. (b) Name the method used for refining silver.

  5. Question 5

    Chemical Reactions and Equations. Asked once: 2025 (same type asked 3 times)

    26
    Translate the following statements into chemical equations and then balance them : (a) Nitric acid reacts with calcium hydroxide to form calcium nitrate and water. (b) Sodium chloride reacts with silver nitrate to form silver chloride and sodium nitrate.