Chemistry - Coordination Chemistry Question with Solution | TestHub

The strength of ligands discussed in spectrochemical series.

According to the limitations of VBT,

It does not give a quantitative interpretation of the thermodynamic or kinetic stabilities of coordination compounds.

 Hybridisation of $\left[\mathrm{Ni}\right(\mathrm{CN}{)}_4]{ }^{-2}$ is ${\mathrm{dsp}}^2$.

The outer electronic configuration of ${\mathrm{Ni}}^{2+}$ ion is $3{\mathrm{d}}^{8}4{\mathrm{s}}^0$.

It is a square planar complex. Cyanide ion is a strong field ligand, thus all electrons will be paired.

One $3\mathrm{d}$, one $4\mathrm{s}$ and two $4\mathrm{p}$orbitals undergo ${\mathrm{dsp}}^2$ hybridization, four equivalent ${\mathrm{dsp}}^2$ hybrid orbitals which are occupied by $4$ electron pairs of $4$ cyanide ligands.

This forms $\left[\mathrm{Ni}\right(\mathrm{CN}{)}_4]{ }^{-2}$

$\mathrm{cis}-[{\mathrm{PtCl}}_2 (\mathrm{en}{)}_2]{ }^{2+}$ complex exhibits optical isomerism, hence, it has two isomers.

Hence statement B and C are correct.