See image — Isomerism and Stereochemistry Chemistry Question

💡 Solution & Explanation

# Identifying Cis Arrangement Around Double Bonds **Understanding Cis Configuration:** For a cis arrangement, identical or similar groups must be on the **same side** of each double bond. **Analyzing Each Option:** **(1)** Two $C=C$ double bonds present. Left bond: H atoms on same side ✓. Right bond: H atoms on same side ✓. However, the overall geometry shows these are on opposite sides relative to the central bond orientation. **(2)** Examining the structure: - First $C=C$: methyl groups on opposite sides (trans) ✗ - Second $C=C$: methyl groups on opposite sides (trans) ✗ **(3)** Linear conjugated system: - First $C=C$: Both terminal carbons on same side (cis) ✓ - Second $C=C$: Both terminal carbons on same side (cis) ✓ - **All double bonds have cis configuration** ✓ **(4)** Two $C=C$ double bonds: - Left bond: methyl groups on opposite sides (trans) ✗ - Right bond: methyl groups on opposite sides (trans) ✗ **Answer: Option (3)** represents a conjugated diene system where both double bonds consistently maintain **cis arrangement** with substituents positioned on the same side of each carbon-carbon double bond.