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Given below are two… (Class 12 Chemistry SQP 2023-24, Q14)

questionbuddy.in/q/cbse-12-chemistry-2023-24-sqp-q14-labelled-strong-oxidising-agents-oxidise

ChemistryCBSE Class 12 · Sample paper, session 2023-24 · 1 mark · Assertion-reason

CBSE Class 12 Chemistry sample paper 2023-24: question 14

From the official CBSE sample question paper for 2023-24, section A, question 14, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q14 · 1 mark · Assertion-reasonCompetency-basedAldehydes, Ketones and Carboxylic Acids

Given below are two statements labelled as Assertion (A) and Reason (R)
Assertion (A): Strong oxidising agents oxidise toluene and its derivatives to benzoic acids.
Reason (R): It is possible to stop the oxidation of toluene at the aldehyde stage with suitable reagents.
Select the most appropriate answer from the options given below:

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

Source: official sample paper from cbseacademic.nic.in (PDF). See it in the full Sample paper 2023-24.

Hints

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

Hint 1

Recall Etard's reaction.

Hint 2

Does R tell us why the acid forms?

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. KMnO₄ oxidises toluene to benzoic acid, so A is true. Etard's reagent (CrO₂Cl₂) or CrO₃/(CH₃CO)₂O stops the oxidation at benzaldehyde, so R is true.

  2. R does not explain why strong oxidants give the acid.

    1 mark

Answer: (B)

Where the marks are

  • Both statements true, R not the explanation (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 paperSample paper 2023-24: 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.