PYQ Vault

Day 143: CBSE Class 10 Science

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

  1. Question 1

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

    34 (B)
    (i) What happens when a small piece of sodium is dropped in ethanol ? Write the equation for this reaction. (ii) Why is glacial acetic acid called so ? (iii) What happens when ethanol is heated at 443 K in the presence of conc. H2SO4\mathrm{H_2SO_4} ? Write the role of conc. H2SO4\mathrm{H_2SO_4} in this case. (iv) Write an equation showing saponification.

  2. Question 2

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 2 times)

    2
    The balanced chemical equation showing reaction between quicklime and water is :

    Tap an option to check your answer.

  3. Question 3

    Electricity. Asked once: 2022 (same type asked 2 times)

    12 (b)
    (a) What is the meaning of electric power of an electrical device ? Write its SI unit. (b) An electric kettle of 2kW is used for 2h. Calculate the energy consumed in (i) kilowatt hour and (ii) joules.

  4. Question 4

    Electricity. Asked once: 2022 (same type asked 2 times)

    12
    (a) A student wants to use an electric heater, an electric bulb and an electric fan simultaneously. How should these gadgets be connected with the mains ? Justify your answer giving three reasons. (b) What is an electric fuse ? How is it connected in a circuit ?

  5. Question 5

    Carbon and its Compounds. Asked once: 2023 (same type asked 5 times)

    36 (A)
    (i) It is observed that covalent compounds are bad conductors of electricity. Give reason. (ii) Carbon can neither form C4+\mathrm{C^{4+}} cation nor C4−\mathrm{C^{4-}} anion. Why ? (iii) Draw electron dot structure of Ethanol. (iv) Identify hetero atom(s) in the following compounds : (a) CH3CH2COCH3\mathrm{CH_3CH_2COCH_3} (b) CH3CH2Cl\mathrm{CH_3CH_2Cl}