The correct order of Cl-O bond order is :

Options

A. `ClO_(3)^(-) lt ClO_(4)^(-) lt ClO_(2)^(-) lt ClO^(-)`
B. `ClO^(-) lt ClO_(4)^(-) lt ClO_(3)^(-) lt ClO_(2)^(-)`
C. `ClO^(-) lt ClO_(2)^(-) lt ClO_(3)^(-) lt ClO_(4)^(-)`
D. `ClO_(4)^(-) lt ClO_(3)^(-) lt ClO_(3)^(-) lt ClO^(-)`

Answer

To determine the bond order of Cl-O in different chlorine oxoanions, we can use the following formula:

**Bond Order = (Valency of Peripheral Atom + Charge on the Radical) / Total Number of Peripheral Atoms**

Let's calculate the bond order for each of the chlorine oxoanions step by step:

### Step 1: Calculate Bond Order for ClO3⁻
1. **Identify the Peripheral Atom**: The peripheral atom is oxygen (O).
2. **Valency of Oxygen**: The valency of oxygen is 2.
3. **Charge on the Radical**: The charge on ClO3⁻ is -1.
4. **Total Number of Peripheral Atoms**: There are 3 oxygen atoms.

**Bond Order Calculation**:
\[ \text{Bond Order} = \frac{(2 + (-1))}{3} = \frac{1}{3} = \frac{5}{3} \approx 1.67 \]

### Step 2: Calculate Bond Order for ClO4⁻
1. **Identify the Peripheral Atom**: The peripheral atom is oxygen (O).
2. **Valency of Oxygen**: The valency of oxygen is 2.
3. **Charge on the Radical**: The charge on ClO4⁻ is -1.
4. **Total Number of Peripheral Atoms**: There are 4 oxygen atoms.

**Bond Order Calculation**:
\[ \text{Bond Order} = \frac{(2 + (-1))}{4} = \frac{1}{4} = \frac{7}{4} \approx 1.75 \]

### Step 3: Calculate Bond Order for ClO2⁻
1. **Identify the Peripheral Atom**: The peripheral atom is oxygen (O).
2. **Valency of Oxygen**: The valency of oxygen is 2.
3. **Charge on the Radical**: The charge on ClO2⁻ is -1.
4. **Total Number of Peripheral Atoms**: There are 2 oxygen atoms.

**Bond Order Calculation**:
\[ \text{Bond Order} = \frac{(2 + (-1))}{2} = \frac{1}{2} = 1.5 \]

### Step 4: Calculate Bond Order for ClO⁻
1. **Identify the Peripheral Atom**: The peripheral atom is oxygen (O).
2. **Valency of Oxygen**: The valency of oxygen is 2.
3. **Charge on the Radical**: The charge on ClO⁻ is -1.
4. **Total Number of Peripheral Atoms**: There is 1 oxygen atom.

**Bond Order Calculation**:
\[ \text{Bond Order} = \frac{(2 + (-1))}{1} = \frac{1}{1} = 1 \]

### Summary of Bond Orders:
- ClO4⁻: Bond Order ≈ 1.75
- ClO3⁻: Bond Order ≈ 1.67
- ClO2⁻: Bond Order = 1.5
- ClO⁻: Bond Order = 1

### Final Order of Bond Orders:
The correct order of Cl-O bond order from highest to lowest is:
1. ClO4⁻ (≈ 1.75)
2. ClO3⁻ (≈ 1.67)
3. ClO2⁻ (1.5)
4. ClO⁻ (1)

Thus, the correct answer is option 3.

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