The oxidation number of iron in the compound formed during the brown ring test for $NO_3^{-}$ ion is . . . . . .

What is the coordination number of $Fe$ in $[Fe(CN)_6]^{3-}$?

On the basis of the following observations made with aqueous solutions,assign secondary valences to metals in the following compounds:

Formula	Moles of $AgCl$ precipitated per mole of the compound with excess $AgNO_3$
$(i) PdCl_2 \cdot 4NH_3$	$2$
$(ii) NiCl_2 \cdot 6H_2O$	$2$
$(iii) PtCl_4 \cdot 2HCl$	$0$
$(iv) CoCl_3 \cdot 4NH_3$	$1$
$(v) PtCl_2 \cdot 2NH_3$	$0$

On complete reaction of $FeCl_3$ with oxalic acid in an aqueous solution containing $KOH$,the product $A$ is formed. The secondary valency of $Fe$ in the product $A$ is $...$ (Round off to the nearest integer).

What are the coordination number and oxidation state of $E$ in the complex $[E(en)_2(C_2O_4)]NO_2$?

Which of the following is a homoleptic complex?