KCET2026ChemistryChemical Bonding and Molecular Structure
With respect to resonance structures of CO ₃²⁻ ion, which of the following statements are correct? (a) All C - O bonds in CO ₃²⁻ are equivalent (b) There are three resonance structures possible for CO ₃²⁻ ion (c) The position of carbon and oxygen should change in every resonance structure (d) The formal charge on carbon atom is -2
Options
- Aa, b and c
- Ba and b only
- Cb and d only
- Da, b and d
Correct answer
B. a and b only
Step-by-step solution
The carbonate ion, CO ₃²⁻ , has three equivalent resonance structures where the double bond is shared among the three oxygen atoms. Due to resonance, all three C - O bonds have partial double bond character and are equivalent in length and strength. Thus, statement (a) is correct. There are exactly three equivalent resonance structures for the CO ₃²⁻ ion. Thus, statement (b) is correct. In resonance structures, the positions of the atoms must remain fixed; only the arrangement of electrons changes. Thus, statement