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Assertion (A) : All… (Class 12 Chemistry 2026, Q16)

questionbuddy.in/q/cbse-12-chemistry-2026-56-5-1-q16-aliphatic-aldehydes-give-positive-fehling

ChemistryCBSE Class 12 · Board exam 2026, set 56/5/1 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry 2026: question 16

Set in the CBSE Class 12 board exam of 2026, paper 56/5/1, section A, question 16, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q16 · 1 mark · Assertion-reasonCompetency-basedAldehydes, Ketones and Carboxylic Acids

Assertion (A) : All aliphatic aldehydes give a positive Fehling’s test.
Reason (R) : Aliphatic aldehydes are reduced by Fehling’s reagent.

  1. (A)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  2. (B)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  3. (C)Assertion (A) is true, but Reason (R) is false.
  4. (D)Assertion (A) is false, but Reason (R) is true.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 56/5/1.

Hints

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

Hint 1

Consider what happens to Cu²⁺ in the test.

Hint 2

Is the aldehyde oxidised or reduced?

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. Aliphatic aldehydes reduce Fehling's solution, giving a red precipitate of , so A is true.

  2. In this reaction the aldehyde is oxidised, not reduced, so R is false. Option (C).

    1 mark

Answer: (C)

Where the marks are

  • A true, R false since aldehydes are oxidised (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Aldehydes, Ketones and Carboxylic Acids, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 56/5/1: 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.