My textbook states that because $sp^2-sp^3$ bonds are stronger than $sp^3-sp^3$ bonds, alkenes are more stable than alkanes. The rule given is that bonds with more $s$ character are stronger.

However, it then states that an alkene with more alkyl substituents at the C=C double bond is stronger than an alkene with just hydrogens attached around the double bonded carbons. Carbon $sp^2-1s$ Hydrogen bond is stronger than Carbon $sp^2-sp^3$ Carbon bond. So how can my textbook use bond strength to explain why the alkyl substituted alkene is more stable than the non-substituted alkene?

  • $\begingroup$ If your understand hyperconjugation in MO theory, you may want to see this: chemistry.stackexchange.com/q/20362/44877 $\endgroup$ Sep 26 '19 at 4:51
  • $\begingroup$ @TanYongBoon thank you. yes this is perfect response! was confused how hyperconjugation applied to case of alkenes vs carbocations $\endgroup$
    – ebehr
    Sep 26 '19 at 5:02
  • $\begingroup$ @TanYongBoon Btw, your profile is very impressive for a HSer. do you have plans of US college and PhD in chemistry in future? $\endgroup$
    – ebehr
    Sep 26 '19 at 5:05
  • $\begingroup$ Welcome to chemistry.SE!. Since you are new here, I advise you to go through the policies of our community. I don't want to sound mean but comment section is not for friendly chatting. I suppose, you have already found what you are looking for. If you have any further doubts, feel free to comment or edit the question. Thank you. $\endgroup$ Sep 26 '19 at 5:53
  • $\begingroup$ @NilayGhosh Does stackexchange have a chat function? $\endgroup$
    – ebehr
    Sep 26 '19 at 7:42

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