would C2H6, C2H4 or C2H2 release the most amount of energy when the carbon-carbon bond is broken?

Answer 1

There are more carbon - hydrogen bonds in C2H6 than in C2H4 or C2H2, so it would contain the most amount of bond energy. It would actually take energy to break these bonds, but energy would be released when new bonds were formed. The question seems a little misleading.