PYQ Vault

Day 171: CBSE Class 10 Science

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

  1. Question 1

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 4 times)

    21
    A metal nitrate ‘A’ on heating gives a metal oxide along with evolution of a brown coloured gas ‘B’ and a colourless gas, which helps in burning. Aqueous solution of ‘A’ when reacted with potassium iodide forms a yellow precipitate. (a) Identify ‘A’ and ‘B’ (b) Name the types of both the reactions involved in the above statement.

  2. Question 2

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 4 times)

    27
    Silver chloride kept in a china dish turns grey in sunlight. (a) Write the colour of silver chloride when it was kept in the china dish. (b) Name the type of chemical reaction taking place and write the chemical equation for the reaction. (c) State one use of the reaction. Name one more chemical which can be used for the same purpose.

  3. Question 3

    Chemical Reactions and Equations. Asked once: 2024 (same type asked 4 times)

    21 (a)
    “No precipitation reaction can occur without exchange of ions between the two reactants.” Justify this statement giving a balanced chemical equation for the reaction.

  4. Question 4

    Chemical Reactions and Equations. Asked once: 2024 (same type asked 4 times)

    5
    Consider the following Chemical equation : a Al2O3\mathrm{Al_2O_3} + b HCl\mathrm{HCl} ⟶\longrightarrow c AlCl3\mathrm{AlCl_3} + d H2O\mathrm{H_2O} In order to balance this chemical equation, the values of a, b, c and d must be

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  5. Question 5

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 4 times)

    3
    Study the following chemical reaction : 2 Na (s)+2 H2O (l)⟶2 NaOH (aq)+H2 (g)↑\mathrm{2\,Na\,(s) + 2\,H_2O\,(\mathit{l}) \longrightarrow 2\,NaOH\,(aq) + H_2\,(g)\uparrow} The reducing agent in this reaction is :

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