Question

Carbon carbon double bond length is stronger than carbon carbon single why

Answer 1

C-C single bond is stronger and is called sigma bond while double bond is weak and is called pie bond
Poe bond is weak because it is formed by hybridation of atomic orbitals

Answer 2

Double bond is more stronger than single bond because, ... Bond length in double bond is 1.34 angstrom while in single bond is 1.54 angstrom where bond length is inversely proportional to bond energy so less bond length, more bond energy is required to break thus it is more stronger bond.