The bond length of `C = O` bond in `CO` is `1.20 Å` and in `CO_(2)` it is `1.34 Å` Then `C = O` bond length in `CO_(3)^(2-)` will be .

Options

A. `1.50Å`
B. `1.34Å`
C. `1.29Å`
D. `0.95Å`

Explanation

To determine the bond length of the `C = O` bond in the carbonate ion `CO3^(2-)`, we can analyze the bond lengths in `CO` and `CO2` and use that information to infer the bond length in `CO3^(2-)`.

### Step-by-Step Solution:

1. **Identify the Bond Lengths in CO and CO2**:
- The bond length of the `C = O` bond in carbon monoxide (CO) is given as `1.20 Å`.
- The bond length of the `C = O` bond in carbon dioxide (CO2) is given as `1.34 Å`.

2. **Understand the Bonding in CO and CO2**:
- In CO, there is a triple bond between carbon and oxygen, which results in a shorter bond length (1.20 Å).
- In CO2, there are two double bonds between carbon and each oxygen atom, resulting in a longer bond length (1.34 Å) compared to CO.

3. **Analyze the Structure of CO3^(2-)**:
- The carbonate ion `CO3^(2-)` has resonance structures. It can be represented as having one double bond and two single bonds among the three oxygen atoms.
- The bond order in carbonate can be calculated as follows:
- There are three resonance structures, and in total, there are 4 bonds (2 double bonds and 2 single bonds across the structures).
- Therefore, the bond order = Total number of bonds / Number of resonance structures = 4 / 3 = 1.33.

4. **Determine the Bond Length in CO3^(2-)**:
- Since the bond order of the `C = O` bond in `CO3^(2-)` is approximately 1.33, which is between a single bond (bond order = 1) and a double bond (bond order = 2), the bond length will be greater than that of a double bond (1.34 Å) and less than that of a single bond.
- Therefore, we can conclude that the bond length of `C = O` in `CO3^(2-)` will be longer than 1.34 Å.

5. **Final Conclusion**:
- Based on the analysis, the bond length of `C = O` in `CO3^(2-)` is expected to be around 1.50 Å, which is consistent with the bond length being longer than in CO2.

### Answer:
The bond length of `C = O` in `CO3^(2-)` is approximately **1.50 Å**.