Species having maximum 'Cl-O' bond order is :

Options

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

Explanation

To determine which species has the maximum 'Cl-O' bond order among the given options, we will calculate the bond order for each species: ClO3^-, ClO2^-, ClO2, and ClO2^-.

### Step 1: Identify the species and their characteristics
We have the following species to analyze:
1. ClO3^-
2. ClO2^-
3. ClO2
4. ClO2^-

### Step 2: Calculate the bond order for each species
The bond order can be calculated using the formula:
\[ \text{Bond Order} = \frac{\text{Number of bonding electrons} - \text{Number of antibonding electrons}}{2} \]

#### For ClO3^-:
1. Count the valence electrons:
- Cl has 7 electrons.
- Each O has 6 electrons, so for 3 O: \( 3 \times 6 = 18 \).
- Total = \( 7 + 18 + 1 \) (for the -1 charge) = 26 electrons.

2. Construct the Lewis structure and determine bonding:
- ClO3^- has 3 bonds to O and one lone pair on Cl.
- Bonding electrons = 6 (3 bonds), Antibonding = 0.

3. Calculate bond order:
\[ \text{Bond Order} = \frac{6 - 0}{2} = 3 \]

#### For ClO2^-:
1. Count the valence electrons:
- Cl has 7 electrons.
- Each O has 6 electrons, so for 2 O: \( 2 \times 6 = 12 \).
- Total = \( 7 + 12 + 1 \) (for the -1 charge) = 20 electrons.

2. Construct the Lewis structure and determine bonding:
- ClO2^- has 2 bonds to O and one lone pair on Cl.
- Bonding electrons = 4 (2 bonds), Antibonding = 0.

3. Calculate bond order:
\[ \text{Bond Order} = \frac{4 - 0}{2} = 2 \]

#### For ClO2:
1. Count the valence electrons:
- Cl has 7 electrons.
- Each O has 6 electrons, so for 2 O: \( 2 \times 6 = 12 \).
- Total = \( 7 + 12 = 19 \) electrons.

2. Construct the Lewis structure and determine bonding:
- ClO2 has 2 bonds to O and no lone pairs on Cl.
- Bonding electrons = 4 (2 bonds), Antibonding = 0.

3. Calculate bond order:
\[ \text{Bond Order} = \frac{4 - 0}{2} = 2 \]

#### For ClO2^-:
1. Count the valence electrons:
- Cl has 7 electrons.
- Each O has 6 electrons, so for 2 O: \( 2 \times 6 = 12 \).
- Total = \( 7 + 12 + 1 \) (for the -1 charge) = 20 electrons.

2. Construct the Lewis structure and determine bonding:
- ClO2^- has 2 bonds to O and one lone pair on Cl.
- Bonding electrons = 4 (2 bonds), Antibonding = 0.

3. Calculate bond order:
\[ \text{Bond Order} = \frac{4 - 0}{2} = 2 \]

### Step 3: Compare the bond orders
- ClO3^-: Bond Order = 3
- ClO2^-: Bond Order = 2
- ClO2: Bond Order = 2
- ClO2^-: Bond Order = 2

### Conclusion
The species with the maximum 'Cl-O' bond order is **ClO3^-** with a bond order of 3.

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