The number of geometrical isomers for $[Pt(NH_3)_2Cl_2]$ is

What will be the value of $x$ in $Fe^{x+}$,if the magnetic moment,$\mu=\sqrt{24} \ BM$?

The number of possible isomers of an octahedral complex $[Co(C_2O_4)_2(NH_3)_2]^-$ is

The number of isomers possible for the square planar complex $K_2[PdClBr_2(SCN)]$ is

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.

Which one of the following coordination complexes exhibits the lowest value of magnetic moment (in $BM$)?