The products $P$ and $Q$ of the following reaction, respectively, are $a S_{8(s)} + b NaOH_{(aq)} \longrightarrow P_{(aq)} + q Q_{(aq)} + r H_2O$

The compound that cannot act both as an oxidising and reducing agent is:

Which among the following species does not show a disproportionation reaction?

Given below are two statements :
Statement $I$: $S_8$ solid undergoes disproportionation reaction under alkaline conditions to form $S^{2-}$ and $S_2O_3^{2-}$.
Statement $II$: $ClO_4^{-}$ can undergo disproportionation reaction under acidic condition.
In the light of the above statements,choose the most appropriate answer from the options given below :

The main products $P$ and $Q$ of the following unbalanced disproportionation reaction are:
$Se_2Cl_2 \rightarrow P + Q$

$1 \text{ mole}$ of $MnO_4^{2-}$ disproportionates into $MnO_4^-$ and $MnO_2$ in an acidic medium. Calculate the percentage by mass of $Mn$ converted to $MnO_4^-$ (Molar mass of $Mn = 55 \ g/mol$).