The isomerism exhibited by $[Co(NH_3)_5(SO_4)]Br$ and $[Co(NH_3)_5(SO_4)]Cl$ is of the ........ type.

The pair$(s)$ of coordination complexes/ions exhibiting the same kind of isomerism is(are)
$(A)$ $[Cr(NH_3)_5Cl]Cl_2$ and $[Cr(NH_3)_4Cl_2]Cl$
$(B)$ $[Co(NH_3)_4Cl_2]^+$ and $[Pt(NH_3)_2(H_2O)Cl]^+$
$(C)$ $[CoBr_2Cl_2]^{2-}$ and $[PtBr_2Cl_2]^{2-}$
$(D)$ $[Pt(NH_3)_3(NO_3)]Cl$ and $[Pt(NH_3)_3Cl]Br$

Explain geometrical isomerism in six-coordinated complex compounds or octahedral complexes.

$A$ coordination complex of type $MX_2Y_2$ ($M$ = metal ion; $X, Y$ = monodentate ligands) can have either a tetrahedral or a square planar geometry. The maximum number of possible isomers in these two cases are respectively:

Which of the following complexes will exhibit optical isomerism?

The spin-only magnetic moment value of $M^{n+}$ ion formed among $Ni$, $Zn$, $Mn$, and $Cu$ that has the least enthalpy of atomisation is $........$ (in nearest integer). Here $n$ is equal to the number of diamagnetic complexes among $K_2[NiCl_4]$, $[Zn(H_2O)_6]Cl_2$, $K_3[Mn(CN)_6]$, and $[Cu(PPh_3)_3I]$.