What is the oxidation state of cobalt in $[Co(NH_3)_6]^{3+}$?

State the rules for the nomenclature of mononuclear coordination compounds.

The oxidation state of $Pt$ in $[Pt(C_2H_4)Cl_3]^-$ is .........

The formula of the complex $Tris(ethylenediamine)cobalt(III)$ sulphate is:

The oxidation number of $Cr$ in $[Cr(NH_3)_6]Cl_3$ is

$Na_2S + Na_2[Fe(CN)_5NO] \to Na_4[Fe(CN)_5NOS]$; what are the oxidation numbers of $Fe$ in the reactant complex and the product complex,respectively?