Nitric oxide, though an odd electron molecule, is diamagenetic in liquid state.

Explanation

To solve the question regarding why nitric oxide (NO), despite being an odd electron molecule, is diamagnetic in its liquid state, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding Nitric Oxide Structure**:
- Nitric oxide (NO) has a total of 15 electrons: nitrogen (N) contributes 7 electrons, and oxygen (O) contributes 8 electrons.
- The electron configuration leads to an unpaired electron in the molecule, making it an odd electron species.

2. **Identifying Magnetic Properties**:
- A molecule is considered paramagnetic if it has unpaired electrons and diamagnetic if all electrons are paired.
- In its gaseous state, NO is paramagnetic due to the presence of the unpaired electron.

3. **Behavior in Liquid State**:
- When NO is in the liquid state, it undergoes a process called dimerization.
- Dimerization involves two NO molecules combining to form a dimer, specifically N2O2.

4. **Pairing of Electrons**:
- During the dimerization process, the unpaired electron from one NO molecule pairs with the unpaired electron from another NO molecule.
- This pairing results in the formation of a stable dimer (N2O2) where all electrons are paired.

5. **Conclusion on Diamagnetism**:
- Since the dimer N2O2 has all paired electrons, it is diamagnetic.
- Therefore, in the liquid state, nitric oxide behaves as a diamagnetic substance due to the dimerization process that pairs the unpaired electrons.

### Final Statement:
Thus, nitric oxide, although an odd electron molecule, is diamagnetic in the liquid state because it dimerizes to form N2O2, where the unpaired electrons are paired up.