page 11 Flashcards
How does the number of R groups bonded to the double-bonded carbons affect alkene stability?
A: The stability of an alkene increases as the number of R groups bonded to the double-bonded carbons increases.
What is the least stable type of alkene according to the substitution pattern?
A: The least stable alkene is ethene (CH₂=CH₂), which has no alkyl groups attached to the double bond.
Rank the stability of alkenes with increasing R group substitution: monosubstituted, disubstituted, trisubstituted, and tetrasubstituted.
A: Monosubstituted < Disubstituted < Trisubstituted < Tetrasubstituted.
Why do more substituted alkenes exhibit greater stability?
A: Increased substitution provides hyperconjugation and inductive electron-donating effects from alkyl groups, which stabilize the double bond.
How does hyperconjugation contribute to alkene stability?
A: Hyperconjugation allows the delocalization of electrons from adjacent C-H bonds into the π system, stabilizing the double bond.
Why is R₂C=CR₂ (tetrasubstituted alkene) the most stable type of alkene?
A: Tetrasubstituted alkenes benefit from maximum hyperconjugation and inductive effects, resulting in greater stabilization.
Which is more stable: RCH=CH₂ (monosubstituted) or R₂C=CH₂ (disubstituted)?
A: R₂C=CH₂ (disubstituted) is more stable due to the additional electron-donating alkyl group.
Why is CH₂=CH₂ less stable than RCH=CH₂?
A: CH₂=CH₂ lacks alkyl substituents that can donate electron density to stabilize the double bond.
What is the effect of steric hindrance on alkene stability?
A: Steric hindrance is minimal in alkenes, so it does not significantly reduce the stability gained from increased substitution.
How does inductive electron donation from alkyl groups stabilize alkenes?
A: Alkyl groups push electron density toward the double bond, compensating for electron deficiency in the π system.
How does inductive electron donation from alkyl groups stabilize alkenes?
A: Alkyl groups push electron density toward the double bond, compensating for electron deficiency in the π system.
