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During photosynthesis… (Class 10 Science SQP 2026-27, Q1)

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ScienceCBSE Class 10 · Sample paper, session 2026-27 · 1 mark · MCQ

CBSE Class 10 Science sample paper 2026-27: question 1

From the official CBSE sample question paper for 2026-27, section A, question 1, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q1 · 1 mark · MCQLife Processes

During photosynthesis, what happens to carbon dioxide and water as glucose is formed?

  1. (A)Carbon dioxide gains hydrogen, while water loses electrons.
  2. (B)Carbon dioxide loses oxygen, while water gains oxygen.
  3. (C)Carbon dioxide is oxidised, while water is reduced.
  4. (D)Both carbon dioxide and water undergo reduction.

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2026-27.

Hints

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

Hint 1

Recall the definitions: gain of hydrogen is reduction and loss of electrons is oxidation.

Hint 2

Which substance releases oxygen gas, and which one ends up as glucose?

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. In photosynthesis, water is split by light energy: . Water loses electrons and hydrogen, so it is oxidised and oxygen is released.

  2. The hydrogen (with the electrons) is added to carbon dioxide to build glucose: . Gaining hydrogen means is reduced.

  3. So carbon dioxide gains hydrogen while water loses electrons. The correct option is (A).

    1 mark

Answer: Option (A): Carbon dioxide gains hydrogen, while water loses electrons.

Where the marks are

  • Selects option (A), since CO₂ is reduced and H₂O is oxidised (1 mark)

Revise the chapter

  • Chapter: Life Processes (notes, formulas, where marks are lost and every past question)
Practise this chapterBoard-style questions from Life Processes, one at a time, marked against the answer key and marking points.Back to the full paperSample paper 2026-27: 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.