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 $[Pt(NH_3)_3Cl]Br$

The metal atom present in the complex $MABXL$ (where $A, B, X$ and $L$ are unidentate ligands and $M$ is metal) involves $sp^3$ hybridization. The number of geometrical isomers exhibited by the complex is:

Which one of the following species responds to an external magnetic field?

Identify the correct pair of properties of the $[Co(NH_3)_6]^{3+}$ complex ion.

$26.7 \ g$ of a compound with the formula $PtCl_2Br_2 \cdot 6H_2O$ is taken for analysis. This compound exhibits stereoisomerism,and a total of $3$ stereoisomers exist. Find the loss in mass (in $g$) when the given amount of the compound is treated with concentrated $H_2SO_4$. (Molar mass: $PtCl_2Br_2 \cdot 6H_2O = 534 \ g \ mol^{-1}$)

$[Ti(H_2O)_6]^{3+}$ is paramagnetic in nature due to