What is the oxidation number of $Cl$ in $HOClO_2$?

Which one has the maximum oxidation number of phosphorus?

In the following reaction,assign the correct category for the underlined atom based on the product of complete hydrolysis at $R.T.$:
$\underline{S}O_2Cl_2 + H_2O \longrightarrow H_2SO_4 + HCl$

$A$ compound contains atoms of three elements $A$,$B$ and $C$. If the oxidation number of $A$ is $+2$,$B$ is $+5$ and that of $C$ is $-2$,the possible formula of the compound is:

In which compound is the oxidation state of phosphorus $+4$?

What is the change in the oxidation state of nitrogen when $HNO_3$ is converted into $N_2O$?