Chemistry - CHEMICAL BONDING Question with Solution | TestHub

The C-H bond length is inversely related to the s-character of the carbon hybrid orbital. In C₂H₆ (ethane), carbon is sp³ hybridized, having the least s-character (25%), leading to the longest C-H bond. C₂H₄ (ethene) is sp² (33% s-character), and C₂H₂ (ethyne) is sp (50% s-character), resulting in shorter C-H bonds. C₂H₂Br₂ has sp hybridization, similar to C₂H₂.

The order of C-H bond lengths is:

C₂H₆ (sp³) > C₂H₄ (sp²) > C₂H₂ (sp)

Therefore, C₂H₆ has the longest C-H bond distance.