Which of the following pair of molecules contain an odd electron molecule and an expanded octet molecule?
Chemical Bonding · Class 11 · JEE Main Previous Year Question
Which of the following pair of molecules contain an odd electron molecule and an expanded octet molecule?
- a
and
- b✓
NO and
- c
and
- d
and NO
NO and
🧠 Two properties to identify: (i) odd-electron molecule — total valence electrons is odd; (ii) expanded octet molecule — central atom from period 3+ has more than 4 bond pairs.
Check odd-electron: NO has valence electrons (odd) → odd-electron molecule ✓
Check expanded octet: — S forms 2 S=O bonds and 2 S–OH bonds (or 4 bonds + expanded resonance), giving S more than 8e. Expanded octet ✓
Eliminate distractors:
- : B has 6e — electron-deficient, not expanded
- : S has 12e — expanded octet, but not odd-electron
Only option (b) pairs an odd-electron molecule (NO) with an expanded-octet molecule ().
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