The pair of species with the same bond order is :

Options

A. NO, CO
B. `N_(2), O_(2)`
C. `O_(2)^(2-), B_(2)`
D. `O_(2)^(+), NO^(+)`

Explanation

To determine the pair of species with the same bond order, we can follow these steps:

### Step 1: Understand Bond Order
Bond order is defined as the number of chemical bonds between a pair of atoms. It can be calculated using the formula:
\[ \text{Bond Order} = \frac{(\text{Number of bonding electrons} - \text{Number of antibonding electrons})}{2} \]

### Step 2: Identify the Given Species
The species given in the question are:
1. NOCO
2. N2O2
3. O2^2-
4. B2
5. O2^+
6. NO^+

### Step 3: Calculate the Bond Order for Each Species
1. **O2^2- (Oxygen Dioxide Ion)**
- Total electrons = 8 (O) + 8 (O) + 2 (for 2 negative charges) = 18
- Bond order = (Number of bonding electrons - Number of antibonding electrons) / 2
- For O2^2-, the bond order is calculated as 1.

2. **B2 (Boron Dimer)**
- Total electrons = 5 (B) + 5 (B) = 10
- Bond order = (Number of bonding electrons - Number of antibonding electrons) / 2
- For B2, the bond order is also 1.

3. **O2^+ (Oxygen Cation)**
- Total electrons = 8 (O) + 8 (O) - 1 (for the positive charge) = 15
- Bond order = 2.5.

4. **N2O2 (Dinitrogen Dioxide)**
- The calculation is complex and generally requires molecular orbital theory, but it typically has a bond order of around 2.

5. **NOCO (Nitrosyl Carbonyl)**
- Similar to N2O2, this requires more complex calculations, but it generally has a bond order of around 2.

### Step 4: Compare the Bond Orders
From the calculations:
- O2^2- has a bond order of 1.
- B2 has a bond order of 1.
- O2^+ has a bond order of 2.5.
- N2O2 has a bond order of around 2.
- NOCO has a bond order of around 2.

### Conclusion
The pair of species with the same bond order is **O2^2- and B2**, both having a bond order of 1.

### Final Answer
The correct option is: **O2^2- and B2**.