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Consider the structures of the… (Class 10 Science 2023, Q7)

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ScienceCBSE Class 10 · Board exam 2023, set 31/1/1 · 1 mark · MCQ

CBSE Class 10 Science 2023: question 7

Set in the CBSE Class 10 board exam of 2023, paper 31/1/1, section A, question 7, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q7 · 1 mark · MCQCarbon and its Compounds

Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from the following :

  1. (A)A and C are isomers of hexane and B is benzene.
  2. (B)A is an isomer of hexane, B is benzene and C is an isomer of hexene.
  3. (C)A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.
  4. (D)A is cyclohexane and B and C are the isomers of benzene.

Figure in the paper: Three six-membered carbon ring structures with hydrogens. (A) ring with all single bonds, each carbon having two H (cyclohexane). (B) ring with alternating double bonds, each carbon having one H (benzene). (C) ring with two double bonds (one on upper right, one on lower left), the remaining carbons carrying two H each (cyclohexadiene). See it in the official paper.

Source: official question paper from cbse.gov.in (PDF). See it in the full 2023 board paper, set 31/1/1.

Hints

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

Hint 1

Look for double bonds in each ring.

Hint 2

Isomers must have the same molecular formula. Count the H atoms in each structure.

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 has only C–C single bonds. It is cyclohexane (), a saturated cyclic hydrocarbon.

  2. B (benzene) and C (cyclohexadiene) both contain C=C double bonds, so both are unsaturated. Their formulas are and , so they are not isomers of each other.

  3. So the correct statement is (C).

    1 mark

Answer: Option (C)

Where the marks are

  • Identifies A as saturated and B, C as unsaturated, option (C) (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 paper2023 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.