$Mn^{2+} + 2e^- \rightarrow Mn,\, $$E^o = - 1.18\, V$
$Mn^{2+} \rightarrow Mn^{3+} + e^-,$ $ E^o = - 1.51 \,V$
The $E^o$ for the reaction $3Mn^{2+} \rightarrow Mn^o + 2Mn^{3+},$
and possibility of the forward reaction are respectively
$2\left(\mathrm{Mn}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Mn}^{2+}\right), E^{\circ}=+1.51 \mathrm{V}$.... $(ii)$
Subtracting Eq. $(ii)$ from Eq. $(i)$, we get
${3 \mathrm{Mn}^{2+} \longrightarrow \mathrm{Mn}+2 \mathrm{Mn}^{3+}}$
${E^{\circ}=-1.18-(+1.51)=-2.69 \mathrm{V}}$
since, the value of $E^{\circ}$ is -ve, therefore the reaction is non-spontaneous
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Statement $I :$ Pure Aniline and other arylamines are usually colourless.
Statement $II :$ Arylamines get coloured on storage due to atmospheric reduction.
In the light of the above statements, choose the most appropriate answer from the options given below: