Nitric oxide (NO) is an important molecule with unique properties. Let's analyze each statement to identify which property it does NOT exhibit.

Step 1: Analyze Magnetic Property

NO has 15 electrons (7 from N + 8 from O). Its molecular orbital configuration is: ${\sigma }_1^2{\sigma }_1^{*}2{\sigma }_2^2{\sigma }_2^{*}2{\pi }_{2px}^2{\pi }_{2py}^2{\pi }_{2px}^{*}1$ The unpaired electron in the π* orbital makes it paramagnetic (attracted to magnetic field), not diamagnetic.

Step 2: Check Reaction with Oxygen

NO readily combines with oxygen: $2\mathrm{NO}+O_2\to 2N{O}_2$ This is a well-known reaction.

Step 3: Determine Oxide Nature

NO does not form acids or bases with water, making it a neutral oxide.

Step 4: Calculate Bond Order

Bond order = (Number of bonding electrons - Number of antibonding electrons)/2 $\frac{10-5}{2}=2.5$ This is correct.

Conclusion

The incorrect property is "It is diamagnetic in gaseous state." NO is paramagnetic due to its unpaired electron.

Related Topics & Formulae

Molecular Orbital Theory: Used to determine electron configuration, bond order, and magnetic properties of molecules.

Bond Order Formula: $\frac{(N_b-N_a)}{2}$ where $N_b$ = bonding electrons and $N_a$ = antibonding electrons.

Paramagnetism: Substances with unpaired electrons are attracted to a magnetic field.

Diamagnetism: Substances with all electrons paired are weakly repelled by a magnetic field.