The oxidation states of $Cr$ in $K_2Cr_2O_7$ and $CrO_5$ are, respectively:

Given below are two statements.
Statement $I$ : In $H_2O_2$, each oxygen atom is assigned an oxidation number of $-1$, and in $RbO_2$, each oxygen atom is assigned an oxidation number of $-\frac{1}{2}$.
Statement $II$ : The representation of $HAuCl_4$ and $MnO_2$ in Stock notation is $HAu(III)Cl_4$ and $Mn(IV)O_2$ respectively.
Examine the above statements and choose the correct answer.

Which one of the following reactions does not involve either oxidation or reduction?

When $KMnO_4$ acts as an oxidising agent and ultimately forms $[MnO_4]^{2-}$,$MnO_2$,$Mn_2O_3$,and $Mn^{2+}$,the number of electrons transferred in each case respectively is:

What is the oxidation number of $Cl$ in $CaOCl_2$?

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