Total number of molecules/species from following which will be paramagnetic is . O 2 , O 2 + , O 2 - , NO , NO 2 , CO , K 2 [ NiCl 4 ] , [ Co ( NH 3 ) 6 ] Cl 3 , K 2 [ Ni ( CN ) 4 ]

Chemistry · Chemical Bonding

JEE Main 2025 — 28 January, Evening Shift — Question 46

Total number of molecules/species from following which will be paramagnetic is___.

$\mathrm{O}_{2}, \mathrm{O}_{2}^{+}, \mathrm{O}_{2}^{-}, \mathrm{NO}, \mathrm{NO}_{2}, \mathrm{CO}, \mathrm{K}_{2}\left[\mathrm{NiCl}_{4}\right]$ ,

$\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{6}\right] \mathrm{Cl}_{3}, \mathrm{~K}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]$

Numerical answer — enter this value.

$\mathrm{O}_{2} \rightarrow 2$ unpaired electrons according to MOT

$\mathrm{O}_{2}{ }^{+} \rightarrow 1$ unpaired electrons according to MOT

$\mathrm{O}_{2}^{-} \rightarrow 1$ unpaired electrons according to MOT

$\mathrm{NO} \rightarrow$ odd electron species

$\mathrm{NO}_{2} \rightarrow$ odd electron species

$\mathrm{K}_{2}\left[\mathrm{NiCl}_{4}\right] \rightarrow \mathrm{Ni}^{2+} \Rightarrow 3 \mathrm{~d}^{8}$ weak Ligand, C.N. $=4$

$\Rightarrow$ Tetrahedral, Paramagnetic with 2 unpaired electrons

Answer key and solution verified before publishing.

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