Th oxidation state of Co in `[Co(EDTA)]^(-1)` is

Options

A. `+3`
B. `-3`
C. `+1`
D. `+2`

Explanation

To determine the oxidation state of cobalt (Co) in the complex ion \([Co(EDTA)]^{-1}\), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the oxidation state variable**:
Let the oxidation state of cobalt be represented as \( x \).

2. **Determine the charge of the ligand (EDTA)**:
The EDTA (ethylenediaminetetraacetic acid) ligand is a hexadentate ligand that typically carries a charge of -4 when it is fully deprotonated.

3. **Set up the equation**:
Since the overall charge of the complex ion \([Co(EDTA)]^{-1}\) is -1, we can set up the equation based on the sum of the oxidation states:
\[ x + (-4) = -1 \]

4. **Solve for \( x \)**:
Rearranging the equation gives:
\[ x - 4 = -1 \]
Adding 4 to both sides results in:
\[ x = -1 + 4 \]
\[ x = +3 \]

5. **Conclusion**:
Therefore, the oxidation state of cobalt in the complex \([Co(EDTA)]^{-1}\) is \( +3 \).

### Final Answer:
The oxidation state of Co in \([Co(EDTA)]^{-1}\) is \( +3 \).

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