2
$\begingroup$

I came across a question :

Which of the following compound does not decolourise an acidified solution of $\ce{KMnO4}$?

Answer was:

$\ce{FeCl3}$

After doing a bit of research I found that $\ce{KMnO4}$ oxidises $\ce{HCl}$ to $\ce{Cl2}$. I doubt whether $\ce{KMnO4}$ would also oxidise chloride ions in case of acidified solution of $\ce{FeCl3}$.

I know that the ferric ion cannot be oxidised further.

$\endgroup$
18
  • 2
    $\begingroup$ Are you sure that "[you] know iron cannot be oxidised further"? Ferrate (IV), Ferrate (V) and Ferrate (VI) oxidation states exist even though the (VI) is the most encountered among the three. $FeCl_3$ has iron (III). $\endgroup$ – Kav May 4 at 13:25
  • $\begingroup$ Have you considered ferric chlorocomplexes ? $\endgroup$ – Poutnik May 4 at 13:27
  • $\begingroup$ @Kav how likely is it that $\ce{Fe(III)}$ can be oxidized further ? Will it do under normal conditions with $\ce{KMnO4}$ or do you require drastic conditions ? $\endgroup$ – Ashish May 4 at 13:31
  • 3
    $\begingroup$ Iron can be oxidized further, but not by KMnO4. $\endgroup$ – Ivan Neretin May 4 at 13:36
  • 1
    $\begingroup$ @Kav Well, ferrates are stronger oxidants than permanganates, and other higher oxidation states of Fe don't exist in water. $\endgroup$ – Ivan Neretin May 4 at 15:06

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.