Question

Select the correct statements about oxygen molecule.

• A. It is paramagnetic
• B. Its bond order is two
• C. In liquid state it is blue coloured
• D. It has two unpaired electrons

Answer 1

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

The correct options are
A It is paramagnetic
B Its bond order is two
C In liquid state it is blue coloured
D It has two unpaired electrons

By MO theory the electronic configuration is:

$O_2$: valence electrons=$6+6=12$

${\left(\sigma 2s\right)}^2{(\sigma \ast 2s)}^2{\left(\sigma 2p\right)}^2{\left(\pi 2p\right)}^4{\left({\pi }^{\ast }2p\right)}^2$

BO=$1/2\times (6-2)=2$;

Therefore it has bond order 2 with two unpaired electrons in ${\pi }^{\ast }2p$ MO that imparts it blue color in liquid state and makes it paramagnetic nature.

Hence, $A,B,C,D$ are correct.