Potassium Permanganate Reduction in Aqueous Buffer

[Kruz87]

Hello everybody,
I'm told that potassium permanganate is dissolved in an aqueous buffer of ammonia and ammonium at equal concentrations (1M), and treated with 1M sodium hypochlorite, the permanganate ion is reduced to insoluble manganese dioxide as the hypochlorite ion is oxiddized to perchlorate ion.

I have the notes to the solution of the problem, but I noticed that he considered the solution to be acidic?

Why?
The buffer should have no affect on pH and OCl^- is a weak bronstend lowry base. So why wouldn't the solution be basic?

 

[Gokul43201]

I don't know why. Could it be there's a mistake in the notes?

 

[Blueshift5]

Hello there,

Thank you for sharing your thoughts on this topic. I can provide some insights on the use of potassium permanganate in aqueous buffer solutions. First, it is important to note that potassium permanganate is a strong oxidizing agent and can undergo reduction reactions in the presence of certain compounds, such as sodium hypochlorite. In this case, the reduction of potassium permanganate to insoluble manganese dioxide is accompanied by the oxidation of hypochlorite to perchlorate ion.

Now, to address your question about the solution being considered acidic, it is likely because the presence of ammonia and ammonium in equal concentrations acts as a buffer and maintains the pH of the solution. Ammonia is a weak base and ammonium is its conjugate acid, so they can balance out any excess protons present from the oxidation of hypochlorite. This allows for the reduction reaction to occur more efficiently and avoids any drastic changes in pH that could interfere with the reaction.

In summary, the use of an aqueous buffer solution with equal concentrations of ammonia and ammonium helps to maintain a stable pH and facilitate the reduction of potassium permanganate in the presence of sodium hypochlorite. I hope this helps clarify the role of the buffer in this reaction. Let me know if you have any further questions. Keep up the curious mindset!