$\mathrm{N}{\mathrm{O}}_2$ and ${\mathrm{N}}_2{\mathrm{O}}_4$ are two forms of nitrogen dioxide. One exists in gaseous state while other in liquid state. The nature of $\mathrm{N}{\mathrm{O}}_2$ and ${\mathrm{N}}_2{\mathrm{O}}_4$ forms are

• A

  both are paramagnetic
• B

  both are diamagnetic
• Correct answer
  C

  $\mathrm{N}{\mathrm{O}}_2$ is paramagnetic while ${\mathrm{N}}_2{\mathrm{O}}_4$ is diamagnetic
• D

  $\mathrm{N}{\mathrm{O}}_2$ is diamagnetic while ${\mathrm{N}}_2{\mathrm{O}}_4$ is paramagnetic

Solution

$\mathrm{N}{\mathrm{O}}_2$ is an odd electron molecule so $\mathrm{N}{\mathrm{O}}_2$ is paramagnetic

The dimer, ${\mathrm{N}}_2{\mathrm{O}}_4$ , has no unpaired electron so it is diamagnetic.

Hence, the correct answer is option: 'C'.