The complex diamminedichloroplatinum $(II)$ has the formula:

The sum of oxidation states of two silver ions in $[Ag(NH_{3})_{2}][Ag(CN)_{2}]$ complex is $....$ .

The oxidation number of nickel in $K_4[Ni(CN)_4]$ is

The complex compound $[Co(NH_3)_3NO_2ClCN]$ is named as

Specify the oxidation numbers of the metals in the following coordination entities:
$(i) [Co(H_{2}O)(CN)(en)_{2}]^{2+}$
$(ii) [CoBr_{2}(en)_{2}]^{+}$
$(iii) [PtCl_{4}]^{2-}$
$(iv) K_{3}[Fe(CN)_{6}]$
$(v) [Cr(NH_{3})_{3}Cl_{3}]$

The compound in which nickel has the lowest oxidation state is