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The body of human beings works… (Class 10 Science 2025, Q3)

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ScienceCBSE Class 10 · Board exam 2025, set 31/2/1 · 1 mark · MCQ

CBSE Class 10 Science 2025: question 3

Set in the CBSE Class 10 board exam of 2025, paper 31/2/1, section A, question 3, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q3 · 1 mark · MCQAcids, Bases and Salts

The body of human beings works within the pH range of :

  1. (A)6.1 to 6.8
  2. (B)6.5 to 7.3
  3. (C)7.0 to 7.8
  4. (D)7.5 to 8.1

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/2/1.

Hints

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

Hint 1

Blood is slightly basic.

Hint 2

The range starts at neutral pH 7.

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. Our body works within a narrow pH range that is close to neutral and slightly basic, about 7.0 to 7.8 (as given in NCERT).

  2. So the correct option is (C) 7.0 to 7.8.

    1 mark

Answer: (C) 7.0 to 7.8

Where the marks are

  • Selects pH range 7.0 to 7.8, option (C) (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Acids, Bases and Salts, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/2/1: 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.