Investigating Redox Reactions Involving Potassium Permanganate

[dajugganaut]

Hi all,

The other day in chemistry class, we carried out several different redox reactions. In one set of the experiments, we reacted potassium permanganate with 3 different potassium halides (KCl, KBr, KI). this particular redox reaction also requires an acidic environment, so sulfuric acid was added.

Some of my friends believe that they saw KBr and KI react with potassium permanganate, but not KCl. I'm looking over the equations for each of the reaction and I can't figure out why KBr and KI would react but not KCl (furthermore, I can't even be sure that KBr and KI reacted at all.)

Does anyone have any ideas?

[ The ON for Mn is 7+ in potassium permanganate. This is the maximum ON for Mn. So naturally, I thought that all reactions would proceed, as bromide, chloride and iodide ions are not at their maximum ON ]

 

[Nate810]

The reason why KCl did not react with potassium permanganate is because the chloride ion does not have a high enough oxidation number to be oxidized by potassium permanganate. The oxidation number of chlorine in KCl is -1, which is too low for it to be oxidized. Bromide and iodide ions, however, have oxidation numbers of +1 and +7 respectively, which are high enough for them to be oxidized. That is why the reaction proceeded with bromide and iodide ions, but not with chloride ions.

 

[quicknote]

Hello,

Thank you for sharing your observations and thoughts on the redox reactions involving potassium permanganate. It is always interesting to investigate and understand the behavior of different substances in chemical reactions.

To address your question, it is important to consider the half-reactions involved in the reaction between potassium permanganate and the potassium halides. In this case, the half-reaction for potassium permanganate is reduction (MnO4- --> Mn2+) while the half-reaction for the potassium halides is oxidation (K+ --> KBr, KI, or KCl).

The reason why KBr and KI may have appeared to react with potassium permanganate while KCl did not could be due to the strength of the oxidizing agent. Potassium permanganate is a strong oxidizing agent, meaning it has a high tendency to accept electrons and undergo reduction. KBr and KI are also strong reducing agents, meaning they have a high tendency to donate electrons and undergo oxidation. Therefore, the reaction between them may have been more noticeable compared to the reaction between KCl, which is a weaker reducing agent.

Additionally, the acidic environment created by the sulfuric acid may have also played a role in the reactions. The acid can help to facilitate the transfer of electrons between the reactants, making the reactions more efficient.

In summary, the differences in reactivity between KBr, KI, and KCl in the redox reactions with potassium permanganate could be attributed to the strength of the oxidizing agent and the presence of an acidic environment. Further experimentation and analysis may be needed to confirm the reactions and determine the exact products formed. I hope this helps to clarify some of your questions and encourages you to continue exploring the fascinating world of redox reactions.