Question

Which of the following statements about the monomer and dimer of $N{O}_2$ is/are not true?

• A. Both are diamagnetic
• B. Both are paramagnetic
• C. The monomer is paramagnetic and the dimer is not
• D. The dimer is paramagnetic and the monomer is not

Answer 1

Answer: (A), (B), (D)

$N{O}_2$ is an odd electron $(7+8+8=23$ electrons) species with the odd electron present on the $N$ atom. Hence, it is paramagnetic. In order to become more stable, the two odd electrons pair up to form a dimer, which is diamagnetic.