Which of the following will have three stereoisomeric forms?
$(i) \ [Cr(NO_3)_3(NH_3)_3]$
$(ii) \ K_3[Co(C_2O_4)_3]$
$(iii) \ K_3[CoCl_2(C_2O_4)_2]$
$(iv) \ [CoBrCl(en)_2]$

The highest value of the calculated spin-only magnetic moment (in $BM$) among all the transition metal complexes is

The $d-$electron configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+}$ and $Co^{2+}$ are $d^4, d^5, d^6$ and $d^7$ respectively. Which one of the following will exhibit minimum paramagnetic behaviour?
(At. nos. $Cr = 24, Mn = 25, Fe = 26, Co = 27$)

Which isomerism is possible in hexa-ammine cobalt$(III)$ hexa-cyanido chromate$(III)$ complex?

Correct increasing order of spin magnetic moment $($in $B.M.)$ for the following complexes is:
$(I) \ [FeF_6]^{3-} \ (II) \ [V(H_2O)_6]^{2+} \ (III) \ [Fe(H_2O)_6]^{2+}$

An octahedral complex having molecular composition $Co \cdot 5NH_3 \cdot Cl \cdot SO_4$ has two isomers $A$ and $B$. The solution of $A$ gives a white precipitate with $AgNO_3$ solution and the solution of $B$ gives a white precipitate with $BaCl_2$ solution. The type of isomerism exhibited by the complex is,