Question

Correct order of stability is :

• A. 1-butene > Trans-2-butene > Cis-2-butene
• B. Trans-2-butene > Cis-2-butene > 1-butene
• C. Trans-2-butene > 1-butene > Cis-2-butene
• D. Cis-2-butene > Trans-2-butene > 1-butene

Answer 1

Answer: (B)

Trans-2-butene > Cis-2-butene > 1-butene

Answer 2

Stability of alkene \hspace20mm \propto\frac{1}{Heat\, of\, hydrogenation\, of\, alkene} Stability of an alkene depends upon the heat of hydrogenation of an alkene. Therefore, the lower the heat of hydrogenation of an alkene, higher will be stability.
Order of stability is
$\, \, \, \, \,$trans-2-butene > cis-2-butene > 1-butene.
Heat of hydrogenation (kJ/mol) are 115.5,119.6 and 126.8 respectively.