Possible products from anion analyses What are possible products from these two anion analyses?


The nitrite test, reacting diphenylamine with a nitrite:


$$
\ce{(C6H5)2NH + NO2- -&gt; ?}
$$


The sulphite test, reacting potassium permanganate with a sulphite:


$$
\ce{KMnO4 + SO3^{2-} -&gt; ?}
$$
Under acidic conditions, a blue colour is observed. This results from the formation of N,N'-diphenylbenzidine. In the course of the reaction, diphenylamine is oxidized to a quinoid radical which subsequently adds to another molecule of diphenylamine. 
Under slightly acidic conditions, bleaching of the solution is observed. Sulfite is oxidized to sulfate while $\ce{MnO4-}$ is reduced to $\ce{Mn^{2+}}$.