Question Detail
Question
Rank the following dienes in order of increasing stability : trans-1,3-pentadiene, cis-1,3-pentadiene, 1,4-pentadiene and 1,2-pentadiene.
Correct Answer
Option A is the correct answer.
Detailed Explanation
The order of increasing stability for dienes is: cumulated dienes (1,2-pentadiene) < isolated dienes (1,4-pentadiene) < conjugated cis dienes (cis-1,3-pentadiene) < conjugated trans dienes (trans-1,3-pentadiene). Conjugated dienes are stabilized by resonance, and trans isomers are more stable than cis.
Hint
How does conjugation and geometry affect diene stability?