PYQ Vault

Day 59: CBSE Class 10 Science

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

  1. Question 1

    Carbon and its Compounds. This type asked 3 times: 2022, 2024, 2025. This one: 2025

    22
    (a) Select from the following the members of same homologous series : (1) CH3−CH2−CHO\mathrm{CH_3{-}CH_2{-}CHO} (2) CH3−CO−CH3\mathrm{CH_3{-}CO{-}CH_3} (3) CH3−CH2−COOH\mathrm{CH_3{-}CH_2{-}COOH} (4) CH3−CH2−CH2−CHO\mathrm{CH_3{-}CH_2{-}CH_2{-}CHO} (b) What happens to (i) the melting point, and (ii) the solubility of compounds as the molecular mass of the compounds in a homologous series increases ?

  2. Question 2

    Carbon and its Compounds. This type asked 3 times: 2022, 2023, 2025. This one: 2025

    36 (a)
    (i) Draw electron dot structure of chlorine molecule. (Atomic Number of Chlorine = 17) (ii) What happens when chlorine reacts with methane in the presence of sunlight ? Write the name of the reaction. (iii) Name the two oxidising agents used for the conversion of alcohols to acids. (iv) List four differences in properties between covalent compounds and ionic compounds.

  3. Question 3

    Chemical Reactions and Equations. This type asked 3 times: 2023, 2024, 2025. This one: 2025

    1
    In the following experimental setup of electrolysis of water, if P and Q are the gases collected in the test tubes enclosing the electrodes R and S, then select the option/options in which the matching is correct : (i) P – Oxygen gas , R – Anode (ii) P – Hydrogen gas , R – Cathode (iii) Q – Hydrogen gas , S – Cathode (iv) Q – Oxygen gas , S – Anode

    Tap an option to check your answer.

  4. Question 4

    Chemical Reactions and Equations. This type asked 3 times: 2023, 2024, 2025. This one: 2025

    3
    Select from the following a statement which is not true about burning of magnesium ribbon in air :

    Tap an option to check your answer.

  5. Question 5

    Chemical Reactions and Equations. This type asked 3 times: 2023, 2024, 2025. This one: 2025

    21
    A student performs the following experiment in his school laboratory. List two observations to justify that in this experiment a chemical change has taken place.