What is the oxidation state of $Cr$ in $[Cr(NH_3)_4Cl_2]^{+}$?

The oxidation state of $Fe$ in $K_3[Fe(CN)_6]$ is .......

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

The oxidation number of $Co$ in the complex ion $[(en)_2Co(\mu-NH_2)(\mu-OH)Co(en)_2]^{3+}$ is:

What is the $IUPAC$ name of $[CoCl_{2}(en)_{2}]^{+}$?

Identify true and false statements:
$(a)$ In the reaction $F_2 + O_2 \to O_2F_2$,oxygen is an oxidising agent.
$(b)$ Among $HClO, HClO_2, HClO_3$ and $HClO_4$,$HClO_2$ is the strongest acid.
$(c)$ Oxidation state of Nickel in $[Ni(CO)_4]$ is zero.
$(d)$ The reaction $BaO_2 + H_2SO_4 \to BaSO_4 + H_2O_2$ is a redox reaction.
The correct order of truth values is: