Question

Resonance in carbonate ion $\left( CO _3{ }^{2-}\right)$ is

Which of the following is true?

• A. All these structures are in dynamic equilibrium with each other.
• B. Each structure exists for equal amount of time.
• C. $CO _3{ }^{2-}$ has a single structure i.e., resonance hybrid of the above three structures.
• D. It is possible to identify each structure individually by some physical or chemical method.

Hint:

In resonance structures, the true molecule or ion is a hybrid of the different structures, and none of the structures exist as distinct entities

Answer 1

The Correct Option is C

Analysis of Resonance in the Carbonate Ion (CO₃²⁻):

The carbonate ion (CO₃²⁻) exhibits resonance, where the true structure is a hybrid of the three resonance structures. These structures are not separate, stable entities but are blended into one. The negative charge is delocalized over the three oxygen atoms, and no single structure can be isolated.

1. Option (4): It is not possible to isolate each individual resonance structure experimentally because the true structure is a resonance hybrid. Hence, Option 4 is false.
2. Option (1): The three resonance structures do not exist in equilibrium with each other. Instead, they are blended into one hybrid structure. Hence, Option 1is false.
3. Option (2): The three resonance structures do not exist for equal amounts of time as separate entities. They are not time-dependent but are a blended average. Hence, Option 2 is false.
4. Option (3): The true structure of CO₃²⁻ is the resonance hybrid of the three possible structures. Hence, Option 3 is correct.

Conclusion: The correct answer is 3.