Among the given compounds I-III, the correct orderof bond dissociation energy of C–H bond markedwith * is:

Answer

Acetylenic C–H (sp hybridized)
– Contains 50% s-character, placing electron density closest to the nucleus.
– This creates the strongest σ-bond and the highest bond dissociation energy (BDE).

Aryl C–H (sp² hybridized)
– Contains 33% s-character, so the electron density is less tightly held.
– The bond is weaker than the acetylenic C–H bond.

Cyclopropane C–H (effectively sp³ hybridized)
– Contains 25% s-character.
– Although ring strain exists, it adds little strength to the bond.
– This results in the weakest C–H bond among the three.