The sum of the oxidation state and the coordination number of the central metal atom is maximum for which of the following complexes?

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

$A$ complex whose $IUPAC$ name is not correctly written is:
Complex $ - $ Name

What is the oxidation state of $Fe$ in $Fe(CO)_5$?

The correct formula of diammine dichlorodicyano chromate $(III)$ is

State the $IUPAC$ name of the following complex: $[Co(H_{2}NCH_{2}CH_{2}NH_{2})_{3}]_{2}(SO_{4})_{3}$