NEET UG CHEMISTRY MCQ: CHEMICAL BONDING & MOLECULAR STRUCTURE

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

$\mathrm{O}_2,$ $\mathrm{O}_2^{+},$ $\mathrm{O}_2^{-},$ $\mathrm{NO},$ $\mathrm{NO}_2,$ $\mathrm{CO},$ $\mathrm{K}_2\left[\mathrm{NiCl}_4\right],$ $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3,$ $\mathrm{K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right]$