The oxidation state of the oxygen atom in potassium superoxide is:

Dichromate ion is treated with base,the oxidation number of $Cr$ in the product formed is .... .

The oxidation number of sulphur in $S_8$ molecule is

Which of the following has been arranged in order of increasing oxidation number of nitrogen?

State whether the following statements are True or False:
$(1)$ The oxidation number of nitrogen in ammonium chloride $(NH_4Cl)$ is $(-3)$.
$(2)$ The oxidation number of $C$ in methyl chloride $(CH_3Cl)$ is $(-2)$.
$(3)$ In the following reaction,the oxidation number of $Br$ changes from $0$ to $+5$: $Br_2 \to BrO_3^-$.

Which one of the following has the highest oxidation number of iodine?