Skip to content

Which one of the following… (Class 10 Science 2026, Q18)

questionbuddy.in/q/cbse-10-science-2026-31-1-1-q18-can-used-acid-base-indicator

ScienceCBSE Class 10 · Board exam 2026, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2026: question 18

Set in the CBSE Class 10 board exam of 2026, paper 31/1/1, section B, question 18, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q18 · 1 mark · MCQCompetency-basedAcids, Bases and Salts

Which one of the following can be used as an acid-base indicator by a visually impaired (blind) student?

  1. (A)Turmeric
  2. (B)Vanilla essence
  3. (C)Methyl orange
  4. (D)Litmus

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

The student cannot see colours. Which other sense could tell an acid from a base?

Hint 2

Look for an indicator whose smell changes in acid or base.

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 blind student cannot see a colour change, so the indicator must signal acids and bases through some other sense, such as smell.

  2. Vanilla essence is an olfactory indicator. Its smell can be detected in acidic solution but is lost in basic solution. Turmeric, methyl orange and litmus all work only by colour change.

    1 mark

  3. Correct option: (B) Vanilla essence.

Answer: Vanilla essence, option (B)

Where the marks are

  • Chooses vanilla essence, an olfactory indicator (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 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.