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Name an alcohol and a… (Class 10 Science 2025, Q34a)

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ScienceCBSE Class 10 · Board exam 2025, set 31/6/1 · 5 marks · Long answer

CBSE Class 10 Science 2025: question 34(a)

Set in the CBSE Class 10 board exam of 2025, paper 31/6/1, section D, question 34(a), for 5 marks. Try it first; the hints and our step-by-step solution are below.

Q34(a) · 5 marks · Long answerCarbon and its Compounds

Name an alcohol and a carboxylic acid having two carbon atoms in their structures. Draw their structures and state how this alcohol can be converted into a carboxylic acid. What happens when these two compounds react in the presence of an acid ? Write chemical equations for the reactions involved in the two cases mentioned above.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2025 board paper, set 31/6/1.

Hints

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

Hint 1

Use the prefix 'eth-' for two carbons: '-ol' for an alcohol and '-oic acid' for an acid.

Hint 2

Turning an alcohol into an acid is oxidation. Which oxidising agents does NCERT use?

Hint 3

An acid and an alcohol react with an acid catalyst to give a sweet-smelling compound. What is that class of compound called?

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. Alcohol with two carbon atoms: ethanol, . Carboxylic acid with two carbon atoms: ethanoic acid, .

    1 mark

  2. Structures:

    • Ethanol: H–C(H)(H)–C(H)(H)–O–H. The first carbon carries 3 H atoms, the second carbon carries 2 H atoms and is bonded to an –OH group.
    • Ethanoic acid: H–C(H)(H)–C(=O)–O–H. A CH₃ group is joined to a carbon that is double bonded to O and single bonded to an –OH group.
    1 mark

  3. Conversion: when ethanol is heated with an oxidising agent such as alkaline potassium permanganate (or acidified potassium dichromate), it is oxidised to ethanoic acid.

    ½ mark

  4. 1 mark

  5. When ethanol and ethanoic acid are warmed together with a little concentrated sulphuric acid (catalyst), a sweet-smelling ester, ethyl ethanoate, is formed. This reaction is called esterification.

    ½ mark

  6. 1 mark

Answer: Ethanol (CH3CH2OH) and ethanoic acid (CH3COOH); oxidation with alkaline KMnO4/acidified K2Cr2O7 converts ethanol to ethanoic acid; with an acid catalyst they form the ester ethyl ethanoate (esterification).

Where the marks are

  • Names ethanol and ethanoic acid (½ + ½ mark)
  • Correct structures of both (½ + ½ mark)
  • States oxidation by alkaline KMnO4 or acidified K2Cr2O7 (½ mark)
  • Oxidation equation (1 mark)
  • States that an ester is formed (½ mark)
  • Esterification equation (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Carbon and its Compounds, one at a time, marked against the answer key and marking points.Back to the full paper2025 board paper, set 31/6/1: 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.