Amongst the following ions,which one has the highest magnetic moment value?
$(i)$ $[Cr(H_2O)_6]^{3+}$
$(ii)$ $[Fe(H_2O)_6]^{2+}$
$(iii)$ $[Zn(H_2O)_6]^{2+}$

The number of optical isomers exhibited by the iron complex $(A)$ obtained from the following reaction is $.........$
$FeCl_3 + KOH + H_2C_2O_4 \rightarrow A$

Which of the following ions is paramagnetic?

The complex with a maximum number of stereoisomers is

If the bidentate ligand ethane-$1, 2$-diamine $(en)$ is progressively added to a green aqueous solution of $[Ni(H_2O)_6]Cl_2$ in the molar ratios $en : Ni$ as $1 : 1, 2 : 1, 3 : 1$,then their associated spin-only magnetic moments (in $B.M.$ unit) are respectively

The number of paramagnetic metal complex species among $[Co(NH_3)_6]^{3+}$,$[Co(C_2O_4)_3]^{3-}$,$[MnCl_6]^{3-}$,$[Mn(CN)_6]^{3-}$,$[CoF_6]^{3-}$,$[Fe(CN)_6]^{3-}$ and $[FeF_6]^{3-}$ with the same number of unpaired electrons is $............$