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Answer the following. (Class 10 Science 2026, Q26)

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ScienceCBSE Class 10 · Board exam 2026, set 31/1/1 · 3 marks · Very short answer

CBSE Class 10 Science 2026: question 26

Set in the CBSE Class 10 board exam of 2026, paper 31/1/1, section B, question 26, for 3 marks. Try it first; the hints and our step-by-step solution are below.

Q26 · 3 marks · Very short answerChemical Reactions and Equations

Answer the following.

  1. (a)

    Name the substance oxidised and reduced in the following reaction: ZnO + C → Zn + CO

    1 mark
  2. (b)

    Balance the following chemical reaction: Pb(NO3)2 + KI → PbI2 + KNO3

    1 mark
  3. (c)

    Give one example each of electrolytic decomposition and decomposition by sunlight.

    1 mark

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/1/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Oxidation is gain of oxygen and reduction is loss of oxygen.

Hint 2

Count the K and NO₃ groups on each side.

Hint 3

Think of passing current through water, and of silver salts kept in sunlight.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. (a) In , carbon gains oxygen, so C is oxidised.

    ½ mark

  2. (a) ZnO loses oxygen, so ZnO is reduced.

    ½ mark

  3. (b) Balanced equation:

    1 mark

  4. (c) Electrolytic decomposition:

    ½ mark

  5. (c) Decomposition by sunlight:

    ½ mark

Answer: (a) C oxidised, ZnO reduced; (b) Pb(NO₃)₂ + 2KI → PbI₂ + 2KNO₃; (c) electrolysis of water; 2AgCl → 2Ag + Cl₂ in sunlight

Where the marks are

  • Substance oxidised: C (½ mark)
  • Substance reduced: ZnO (½ mark)
  • Correctly balanced equation (1 mark)
  • Example of electrolytic decomposition (½ mark)
  • Example of photolytic decomposition (½ mark)

Revise the chapter

Practise this chapterBoard-style questions from Chemical Reactions and Equations, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/1/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.