Question

There are four complexes of Ni. Select the complexes/es which will be attracted by magnetic field:

(I) ${\left(\left[Ni{\left(CN\right)}_4\right]\right)}^{2-}$ (II) ${\left[NiC{l}_4\right]}^{2-}$ (III) $\left[Ni{\left(CO\right)}_4\right]$ (IV) ${\left(\left[Ni{\left(N{H}_3\right)}_6\right]\right)}^{2+}$

• A. I only
• B. II only
• C. II, III and IV
• D. II and IV

Answer 1

Answer: (D)

Only ${\left[NiC{l}_4\right]}^{2-}$ and ${\left(\left[Ni{\left(N{H}_3\right)}_6\right]\right)}^{2+}$ are paramagnetic so will be attracted in magnetic field.

Complex	O.S	HBZ	Geometry	Unpaired	Magnetic property
${\left[NiC{l}_4\right]}^{2-}$	+2	$s{p}^3$	Tetrahadral	2	Paramagnetic
${\left(\left[Ni{\left(CN\right)}_4\right]\right)}^{2-}$	+2	$ds{p}^2$	Square planar	0	Diamagnetic
$\left[Ni{\left(CO\right)}_4\right]$	0	$s{p}^3$	Tetrahadral	0	Diamagnetic
${\left(\left[Ni{\left(N{H}_3\right)}_6\right]\right)}^{2+}$	+2	$s{p}^3{d}^2$	Octahedral	2	Paramagnetic