Q1. [1] § 4.2.2 Chains, Branches and Rings
Consider the structures of the three cyclic carbon compounds A, B and C given below and select the correct option from the following :
- (a) A and C are isomers of hexane and B is benzene.
- (b) A is an isomer of hexane, B is benzene and C is an isomer of hexene.
- (c) A is a saturated cyclic hydrocarbon and B and C are unsaturated cyclic hydrocarbons.
- (d) A is cyclohexane and B and C are the isomers of benzene.
Previously asked in CBSE board exam
2023 31/1/1 Q7
Generated by claude-sonnet-4-6 · 2026-06-15 06:50 · grounding rag
Model Answer
The correct option is (c): A is a saturated cyclic hydrocarbon (cyclohexane, C₆H₁₂) and B and C are unsaturated cyclic hydrocarbons (both contain double bonds).
Explanation
- A = cyclohexane (C₆H₁₂) — fully saturated ring; it is an isomer of hexene (not hexane, as hexane is C₆H₁₄ with a different formula).
- B = benzene (C₆H₆) — unsaturated, with alternating double bonds.
- C — also an unsaturated cyclic compound with double bond(s); it is not an isomer of benzene (different formula/structure).
- Option (a) and (b) are wrong because cyclohexane is NOT an isomer of hexane (C₆H₁₄ ≠ C₆H₁₂). Option (d) is wrong because C is not an isomer of benzene. Only option (c) correctly classifies all three on the basis of saturation.
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