Question

There are four complexes of Ni. Select the complex(es) which will be attracted by a magnetic field.

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

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

Answer 1

The correct option is D II and IV

Paramagnetic complexes will be attracted by the magnetic field.

$[NiC{l}_4{]}^{2-}$ and $\left[Ni\right(H_{2}O{)}_6{]}^{2+}$ contain 2 unpaired electrons each. Thus they are paramagnetic and will be attracted by the magnetic field.

In $\left[Ni\right(CN{)}_4{]}^{2-}$ and $\left[Ni\right(CO{)}_4]$, all the electrons are paired. Hence, they are diamagnetic substances and are not attracted by the magnetic field.

Hence option D is correct.