Question

Which of the following statements is incorrect for the coordination compound
$K_2\left[Cr\right(NO{)}^{+}\left(N{H}_3\right)\left(CN{)}_4\right]$:

• A. Its IUPAC name is pottassium amminetetracyanidonitrosoniumchromate(I)
• B. Its spin only magnetic moment is $\sqrt{8}$ BM
• C. Its hybridization is $d^{2}s{p}^3$
• D. It exhibits geometrical isomerism

Answer 1

The correct option is B Its spin only magnetic moment is $\sqrt{8}$ BM

The name of the complex is pottassium amminetetracyanidonitrosoniumchromate(I).
In this complex $Cr$ is in a +1 oxidation state and $C{N}^{-}$ is a strong field ligand. So, electrons will be paired up and hybridisation will take place as given below.

One $e^{-}$ is unpaired in the 3d subshell so the magnetic moment = $\sqrt{1(1+2)}=\sqrt{3}BM$.
The complex can either be in the cis or trans form, so it exhibits geometrical isomerism.