Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen?

What is the oxidation state of $Cr$ in potassium dichromate?

Oxidation number of oxygen in potassium superoxide $(KO_2)$ is

What is the oxidation state of chlorine atom in chloric acid?

Assign oxidation number to the underlined elements in each of the following species:
$(a)$ $NaH_2\underline{P}O_4$
$(b)$ $NaH\underline{S}O_4$
$(c)$ $H_4\underline{P_2}O_7$
$(d)$ $K_2\underline{Mn}O_4$
$(e)$ $Ca\underline{O_2}$
$(f)$ $Na\underline{B}H_4$
$(g)$ $H_2\underline{S_2}O_7$
$(h)$ $KAl(\underline{S}O_4)_2 \cdot 12H_2O$

In the following reaction,assign the state for the underlined atom for the product of complete hydrolysis at $R.T.$:
$\underline{Cl}F + H_2O \longrightarrow HOCl + HF$