The correct increasing order of C–H, C–O, C=O and C≡N bonds in terms of covalent bond length is
Q. 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 :
A. D < C < B < A
B. D < C < A < B
C. A < B < C < D
D. A < D < C < B
Correct Answer: D

Explanation (Detailed & Concept Based)

Bond length depends mainly on:

• Bond order (single > double > triple in length)

• Size of atoms involved

Step 1: Compare bond orders

C≡N is a triple bond → shortest among C–O, C=O and C≡N.

C=O is a double bond → shorter than single C–O but longer than triple bond.

C–O is a single bond → longer than C=O.

Step 2: Consider C–H bond

Hydrogen is very small in size. Even though C–H is a single bond, it is shorter than C–O single bond because hydrogen atom is much smaller than oxygen.

Approximate bond lengths:

C–H ≈ 1.09 Å

C≡N ≈ 1.16 Å

C=O ≈ 1.21 Å

C–O ≈ 1.43 Å

Arranging in increasing order (shortest to longest):

C–H < C≡N < C=O < C–O

Using given labels:

A < D < C < B

Correct Option: D

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Updated for JEE Main 2026: This PYQ is important for JEE Mains, JEE Advanced and other competitive exams. Practice more questions from this chapter.

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