Which of the following properties is not shown by `NO` ?

Options

A. its bond order is 2.5
B. lts is diamagnetic in the gaseous state
C. lt is a netural oxide
D. lts combines with oxygen to from nitrogen dioxide.

Explanation

To determine which property is not shown by nitric oxide (NO), we will analyze the properties provided in the question step by step.

### Step 1: Understanding Bond Order
To calculate the bond order of NO, we need to know the number of electrons in the molecule. NO has a total of 15 electrons. The molecular orbital configuration of NO can be written as follows:

- σ1s²
- σ*1s²
- σ2s²
- σ*2s²
- σ2p²
- π2p²
- π*2p¹

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

From the configuration:
- Bonding electrons: 10 (from σ and π orbitals)
- Antibonding electrons: 5 (from σ* and π* orbitals)

Thus, the bond order is:
\[ \text{Bond Order} = \frac{(10 - 5)}{2} = 2.5 \]

### Step 3: Analyzing Magnetic Properties
Next, we need to determine the magnetic properties of NO. A molecule is considered:
- **Diamagnetic** if all electrons are paired.
- **Paramagnetic** if there are unpaired electrons.

In the case of NO, the last electron is in a π* orbital, which is unpaired. Therefore, NO is **paramagnetic**, not diamagnetic.

### Step 4: Checking Neutrality
NO is a neutral molecule, as it does not carry any charge. This property is true.

### Step 5: Reactivity with Oxygen
NO can react with oxygen to form nitrogen dioxide (NO2). This is a true statement as well.

### Conclusion
From the analysis, the property that is **not shown by NO** is that it is **diamagnetic in nature**. Instead, it is **paramagnetic** due to the presence of an unpaired electron.

### Final Answer
The property that is not shown by NO is that it is **diamagnetic in nature**.

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