Chemistry - GOC Question with Solution | TestHub
How many of the following statements are correct regarding resonance?
1. Resonance involves delocalisation of electrons.
2. In resonance, the positions of nuclei remain unchanged.
3. Only π-electrons can participate in resonance.
4. Lone pairs can also participate in resonance.
5. Resonance structures are imaginary and do not exist separately.
6. The actual molecule is more stable than any one canonical form.
7. All resonance structures always contribute equally to the resonance hybrid.
8. The σ-bond framework remains unchanged during resonance.
Answer:
Solution:
Statements 1, 2, 4, and 8 are correct because resonance only involves shifting -electrons and lone pairs while keeping nuclei and -bonds perfectly stationary.
Statement 3 is incorrect since non-bonding lone pairs routinely participate in delocalization alongside -electrons (as seen in aniline or phenol).
Statements 5 and 6 are correct because individual canonical structures are imaginary contributing forms, while the real molecule is a single, highly stable resonance hybrid.
Statement 7 is incorrect because contributing structures do not contribute equally; more stable structures (with fewer formal charges or complete octets) have a greater contribution.
