Question
The correct increasing order of C-H(A), C-O(B), C=O(C) and C N(D) bonds in terms of covalent bond length is:
JEE Main
Chemistry
Chemical Bonding and Molecular Structure
2026
JEE Main 2026 (21 January Shift 2)
JEE Main Chemistry Question (2026) — Solution
Options
- A. D < C < A < B
- B. A < D < C < B
- C. D < C < B < A
- D. A < B < C < D
Answer
B. A < D < C < B
Step-by-step solution
Bond lengths depend on bond multiplicity and atomic sizes. C-H (single) ≈ 1.09 Å, C-O (single) ≈ 1.43 Å, C=O (double) ≈ 1.23 Å, C≡N (triple) ≈ 1.16 Å. Triple bonds are shorter than double bonds, which are shorter than single bonds. For single bonds, C-O is longer due to lower electronegativity difference compared to C-H. Increasing order of bond length: C-H (A) < C N (D) < C = O (C) < C-O (B), giving A < D < C < B.
Related: Chemistry — Chemical Bonding and Molecular Structure · All PYQ Banks