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QJEEAdv21Ch1c1c: JEE Advanced 2021 Chemistry - Class 11 JEEAdv21Ch1c1c Solution: Correct match of the C-H bonds (shown in bold) in Column J with …
Correct match of the C-H bonds (shown in bold) in Column J with their BDE in Column K is
| Column J Molecule | Column K BDE (kcal ) |
|---|---|
| (P) H-CH( ) | (i) 132 |
| (Q) H-CH Ph | (ii) 110 |
| (R) H-CH=CH | (iii) 95 |
| (S) H-C CH | (iv) 88 |
Multiple Choice 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 - ii
Step-by-Step Verified Solution
A more stable radical means lesser the bond dissociation energy.
Radicals formed are
Radical formed from Q (PhCH2 H) is most stable due to resonance.
Stability of free radical decreases with increase in % s-character.
P radical sp3 % s-character 25%
R radical sp2 % s-character 33%
S radical sp % s-character 50%
Thus, order of stability of free radical is
Q > P > R > S
Order of bond dissociation energy is
S > R > P > Q