JEE Advanced2021ChemistryGeneral Organic ChemistryActual
Paragraph: The amount of energy required to break a bond is same as the amount of energy released when the same bond is formed. In gaseous state, the energy required for homolytic cleavage of a bond is called Bond Dissociation Energy (BDE) or Bond Strength. BDE is affected by s -character of the bond and the stability of the radicals formed. Shorter bonds are typically stronger bonds. BDEs for some bonds are given be
Options
- AP - iii ,   Q - iv ,   R - ii ,   S - i
- BP - i ,   Q - ii ,   R - iii ,   S - iv
- CP - iii ,   Q - ii ,   R - i ,   S - iv
- DP - ii ,   Q - i ,   R - iv ,   S - iii
Correct answer
A. P - iii ,   Q - iv ,   R - ii ,   S - i
Step-by-step solution
Relative stability of radicals : C ∙ sp ≡ CH > C ∙ H sp 2 = CH 2 > C ∙ H 2 − Ph sp 3   Resonance   stabilized > C ∙ H CH 3 2 sp 3 So, BDE H − C ≡ CH H − CH = CH 2 H − CH 2 − Ph H − CH CH 3 2 BDE 132 110 88 95 Electronegativity ∝   %   s - character ∝ bond strength ∝ BDE