MCQ
Which one of the following molecules is paramagnetic?
  • A
    $N_2$
  • B
    $NO$
  • $CO$
  • D
    $O_3$

Answer

Correct option: C.
$CO$
c
The molecular orbital configuration of the molecules given is 

Total no. of electrons in $NO$

$=7(N)+8(O)=15$ 

Hence $E.C.$ of $NO$

$KK{[\sigma 2s]^2}{[{\sigma ^*}(2s)]^2}{[\sigma 2{p_z}]^2}$ 

                           ${[\pi (2{p_x})]^2}[\pi {(2{p_y})^2}]{[{\pi ^*}(2{p_x})]^1}$

Due to presence of one unpaired electron

$NO$ is paramagnetic.

Except $NO$ all are diamagnetic dur to absence of unpaired electrons.

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