Question

Which of the following compound is paramagnetic:

• A. Tetracyanonickelate (II) ion
• B. Tetraamminezinc (II) ion
• C. Hexaaminechromium (III) ion
• D. Diamminesilver (I) ion

Answer 1

The correct option is C Hexaaminechromium (III) ion

$\left(A\right)\left[Ni\right(CN{)}_4{]}^{2-}$
$N{i}^{2+}$ has electronic configuration: $3d^{8}4s^0$
This complex is diamagnetic because due to the presence of a strong field ligand all electrons gets paired up.
$\left(B\right)\left[Zn\right(N{H}_3{)}_4{]}^{2+}$ is diamagnetic in nature.
$Z{n}^{2+}$ has electronic configuration: $3d^{10}4s^0$
$\left(C\right)\left[Cr\right(N{H}_3{)}_6{]}^{3+}$ is paramagnetic due to the presence of unpaired eletrons.
$C{r}^{3+}$ has electronic configuration: $3d^{3}4s^0$
$\left(D\right)\left[Ag\right(N{H}_3{)}_2{]}^{+}$ is diamagnetic due to absence of unpaired electron in it.
$A{g}^{+}$ has electronic configuration: $4d^{10}5s^0$