Which of the following isomerism is not possible for complexes having molecular formulas:
$(i) \ Pt(SCN)_2 \cdot 3PEt_3$
$(ii) \ CoBr \cdot SO_4 \cdot 5NH_3$
$(iii) \ FeCl_3 \cdot 6H_2O$

Consider the following statements and select the correct option using the codes given.
$(i)$ $[Cr(NH_3)_6][Cr(CN)_6]$ and $[Cr(NH_3)_4(CN)_2][Cr(NH_3)_2(CN)_4]$ are coordination isomers.
$(ii)$ $[Cr(py)_2(H_2O)_2Cl_2]Cl$ and $[Cr(py)_2(H_2O)Cl_3]H_2O$ are linkage isomers.
$(iii)$ $[Pt(NH_3)_4Br_2]Cl_2$ and $[Pt(NH_3)_4Cl_2]Br_2$ are linkage isomers.
$(iv)$ $[NiCl_2(PPh_3)_2]$ (tetrahedral) exhibits geometrical isomerism.

The complex that can exhibit linkage isomerism is

The following complexes are given:
$1$. $\text{trans}-[Co(NH_3)_4Cl_2]^+$
$2$. $\text{cis}-[Co(NH_3)_2(en)_2]^{3+}$
$3$. $\text{trans}-[Co(NH_3)_2(en)_2]^{3+}$
$4$. $[NiCl_4]^{2-}$
$5$. $[TiF_6]^{2-}$
$6$. $[CoF_6]^{3-}$
Choose the correct code:

The compound$(s)$ that exhibit$(s)$ geometrical isomerism is(are):
$A$. $[Pt(en)Cl_2]$
$B$. $[Pt(en)_2]Cl_2$
$C$. $[Pt(en)_2Cl_2]Cl_2$
$D$. $[Pt(NH_3)_2Cl_2]$

The pair in which both the species have the same magnetic moment (spin only) is :