PYQ Vault

Day 74: CBSE Class 10 Science

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

  1. Question 1

    Our Environment. Asked once: 2026 (same type asked 5 times)

    12
    Suggest one precaution to be taken before disposing of the following : (a) Sewage from homes (b) Industrial wastes

  2. Question 2

    Carbon and its Compounds. Asked once: 2025 (same type asked 4 times)

    34 (a)
    (a) Define the term “Functional group of a carbon compound”. Write the formula of functional group present in (i) propanol and (ii) propanone. (b) Name the process of conversion of (i) ethanol to ethene and (ii) ethanol to ethanoic acid. Write the reaction equation stating the conditions required for each of the reactions to occur.

  3. Question 3

    Chemical Reactions and Equations. Asked once: 2026 (same type asked 4 times)

    26
    Account for the following : (a) White silver chloride turns grey when exposed to sunlight. (b) Lead (II) nitrate on heating releases brown fumes. (c) Bags of oil and fat containing food items are flushed with nitrogen gas.

  4. Question 4

    Chemical Reactions and Equations. Asked once: 2025 (same type asked 4 times)

    21
    Name the compound used in black and white photography. State whether the reaction that occurs is exothermic or endothermic. Give justification for your answer.

  5. Question 5

    Chemical Reactions and Equations. Asked once: 2025 (same type asked 4 times)

    27 (B)
    Define a precipitation reaction. Give its example and also express the reaction that occurs in the form of a balanced chemical equation.