What is the oxidation number of sulfur in $H_2SO_5$?

Arrange the following substances in the increasing order of the oxidation number of $Mn$: $MnCl_2, MnO_2, Mn(OH)_3, KMnO_4$.

Consider the following molecules: $Br_3O_8$,$F_2O$,$H_2S_4O_6$,$H_2S_5O_6$,and $C_3O_2$. Count the number of atoms existing in their zero oxidation state in each molecule. Their sum is . . . . .

What is the oxidation number of sulfur in $Na_2S_4O_6$?

The oxidation state of chlorine in $KClO_4$ is

Assertion: In some cases,oxygen exhibits a positive oxidation state. Consequently,it is an electronegative element.
Reason: Fluorine is more electronegative than oxygen.