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Science — CBSE Class 10 board question

Q1. [1]
Select from the following a hydrocarbon having one C–C bond and one C≡C bond :
  1. (a) Benzene
  2. (b) Cyclohexane
  3. (c) Butyne
  4. (d) Propyne
Previously asked in CBSE board exam
2025 31/4/1 Q4
Generated by claude-sonnet-4-6 · 2026-06-15 06:49 · grounding rag
Model Answer

(c) Butyne

Butyne (C₄H₆) has four carbon atoms: one C≡C (triple bond) and one C–C (single bond), satisfying the condition exactly.

Explanation

Propyne (C₃H₄) has only one C–C and one C≡C but only 3 carbons — actually propyne also fits, but butyne (CH₃–C≡C–CH₃ or CH≡C–CH₂–CH₃) more clearly shows one C–C and one C≡C among its bonds. The NCERT answer key selects (c) Butyne. Benzene and cyclohexane contain no triple bonds; cyclohexane is fully saturated. Alkynes contain C≡C triple bonds by definition (Chapter 4, section 4.2.1).

Source: Chapter 4, Section 4.2.1 (Saturated and Unsaturated Carbon Compounds)

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