Hi can someone explain the science behind why C-C double bond is LESS than twice the strength of the C-C single bond? I came across it in a question and although I knew it was true I didn’t know exactly why. Thanks in advance!

Hi!

Because in C=C we have a higher bond energy and the bond energy is less than two times higher than the bond energy of C-C , so it’s strength is less than twice of the single bond.

Yes I know that it is about the bond energy but why LESS than twice and not twice the strength since there are double the amount of bonds?

This is the reason .

For instance, the H atoms are small and can get close to one another. The C=C double bond is not quite twice as strong as a single bond because the second shared electron pair does not have as favorable geometry for bonding as does the first pair.

Heyy, the double bond is made of 1 sigma and 1 pi bond. The pi bond is weaker than sigma, so the C=C is not exactly 2x stronger than C-C… (would have to have exactly 2 sigma bonds between carbons which is impossible)

Yesss this makes a lot of sense thank you! I was wondering about the strength of the pi bond!!