JEE Advanced
Chemistry
General Organic Chemistry
2021
JEE Advanced 2021 (Paper 2)
JEE Advanced Chemistry Question (2021) — Solution
Question
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 below: Question: Correct match of the C - H bonds (shown in bold) in Column J with their BDE in Column K is
Options
- A. P - iii ,   Q - iv ,   R - ii ,   S - i
- B. P - i ,   Q - ii ,   R - iii ,   S - iv
- C. P - iii ,   Q - ii ,   R - i ,   S - iv
- D. P - ii ,   Q - i ,   R - iv ,   S - iii
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
Practice more on Quantrex App →
Related: Chemistry — General Organic Chemistry · All PYQ Banks