Question

The pair(s) of reagents that yield paramagnetic species is/are :

• A. $Na$ and excess $N{H}_3$
• B. $K$ and excess $O_2$
• C. $Cu$ and dilute $HN{O}_3$
• D. $O_2$ and 2-ethylanthraquinol

Answer 1

Answer: (A), (B), (C)

The correct options are
A

$Na$ and excess $N{H}_3$

B

$K$ and excess $O_2$

C

$Cu$ and dilute $HN{O}_3$

$Na$ and excess $N{H}_3$ produces solvated electrons – which is highly reducing in nature. Because of the presence of the electrons, the system is paramagnetic.

$K+O_2⟶K{O}_2$

Again, the superoxide anion is paramagnetic. Cu in dilute HNO_3 gives nitrous oxide and copper (II) nitrate – both of which are paramagnetic.

$O_2$ and 2-ethylanthraquinol is a cyclic oxidation-reduction that yields $H_2{O}_2$ in the oxidation part. Hydrogen peroxide is diamagnetic.