Chemical Bonding - Result Question 51

26. Among $KO _2, AlO _2^{-}, BaO _2$ and $NO _2^{+}$, unpaired electron is present in

(1997 C, 1M)

(a) $NO _2^{+}$ and $BaO _2$

(b) $KO _2$ and $AlO _2^{-}$

(c) Only $KO _2$

(d) Only $BaO _2$

Show Answer

Answer:

Correct Answer: 26. (c)

Solution:

  1. Molecular orbital electronic configuration are

alt text

Has one unpaired electron in $\stackrel{*}{\pi} 2 p$ orbital.

$AlO _2^{-}$ has both oxygen in $O^{2-}$ state, therefore, no unpaired electron is present.

alt text

Has no unpaired electron.

$NO _2^{+}$ has $[O=\stackrel{+}{N}=O]$ bonding, hence no unpaired electron.