Question

Among $NO_{2}^{+}$ , KO₂ and Na₂O₂ and NaAlO₂­ , the paramagnetism exist in-

• A. Na₂O₂ only
• B. KO₂ and $NO_{2}^{+}$
• C. Na₂O₂ and NaAlO₂
• D. KO₂ only

Answer 1

Answer: (D)

KO₂ only

Answer 2

The electron distribution in O₂ is :

$\sigma_{1s}^{2}$ $\sigma_{2p_{x}}^{2}$ $\pi_{2p_{y}}^{2}$ $\pi_{2p_{y}}^{*^{1}}$ $\pi_{2p_{Z}}^{*^{1}}$

\ $O_{2}^{2 -}$ is diamagnetic and $O_{2}^{-}$ is paramagnetic. In Al$O_{2}^{-}$, oxide ions (O^2–) are present

and oxide ion is diamagnetic.

NO₂ has one unpair electron hence paramagnetic but $NO_{2}^{+}$ has no unpair electron therefore diamagnetic.