Arrange the following haloalkanes in increasing order of carbon-halogen ( C-X) bond enthalpies.
A. CH3-Br
B. CH3-Cl
C. CH3-I
D. CH3-F
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → C < A < B < D
The strength of a carbon–halogen bond depends on the size of the halogen atom. From fluorine to iodine the halogen atom becomes larger, its orbitals overlap less effectively with the orbital of carbon, and the C–X bond becomes longer and weaker.
With the given labels:
C. \( \ce{CH3-I} \) < A. \( \ce{CH3-Br} \) < B. \( \ce{CH3-Cl} \) < D. \( \ce{CH3-F} \)
Shortcut: The C–I bond (C) is the weakest and the C–F bond (D) is the strongest. Only Option (4) starts with C and ends with D.
NCERT (2026-27 edition):
Nature of C-X Bond – …
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| 26-05 S1 14-05 S2 | – | – | – | – |