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Question #44200

Difficulty: 8/10 | 🟢 Free

The Question

Consider the isoelectronic diatomic pair \ce{CO} and \ce{NO+}, and the isoelectronic linear triatomic pair \ce{CO2} and \ce{NO2+}. Let $d_{\ce{CO}}$ , $d_{\ce{NO^+}}$ , $d_{\ce{CO_2}}$ , and $d_{\ce{NO_2^+}}$ represent their respective equilibrium bond lengths. Based on Molecular Orbital Theory, effective nuclear charge ( $Z_{\text{eff}}$ ), and orbital mixing, which of the following correctly sequences these bond lengths?

Options

A.
$d_{\ce{NO^+}} < d_{\ce{CO}} < d_{\ce{NO_2^+}} < d_{\ce{CO_2}}$
B.
$d_{\ce{CO}} < d_{\ce{NO^+}} < d_{\ce{CO_2}} < d_{\ce{NO_2^+}}$
C.
$d_{\ce{NO^+}} < d_{\ce{CO}} < d_{\ce{CO_2}} < d_{\ce{NO_2^+}}$
D.
$d_{\ce{CO}} < d_{\ce{NO^+}} < d_{\ce{NO_2^+}} < d_{\ce{CO_2}}$

Check Your Answer

Correct Answer

Step-by-Step Solution

Explanation

How the Examiner Thinks

Mechanism_Trap

Don't get tricked by the process! Learn the mechanical traps used in competitive exam questions.

Concepts Behind This Question

Molecular Orbital Mixing|Resonance Energy and Stability

Why This Question Is Tricky

Common Mistakes

This problem tests the interplay between Molecular Orbital Theory (bond order), effective nuclear charge ( $Z_{\text{eff}}$ ), and $s-p$ mixing across isoelectronic series.

The 'Hidden Variable' is the dominance of the central atom's $Z_{\text{eff}}$ in contracting bond lengths for isoelectronic polyatomic species with identical bond geometries.

A common student trap is assuming that polyatomic resonance structures (like \ce{NO2+}) might have longer bonds than their neutral counterparts (\ce{CO2}) due to cationic repulsion or misapplied steric arguments, failing to recognize that the smaller covalent radius of Nitrogen dictates the bond length.

Quick Facts About This Question

Question Information

Subject	Chemistry
Chapter	Chemical Bonding and Molecular Structure - Class 11 Part 1
Concept	Molecular Orbital Mixing
Difficulty	8
Cognitive Load	7
Target Solve Time	160 sec
Access	Free