Why do Manganate(VII) ions need scidic conditions?

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Manganate(VII) ions require acidic conditions to effectively function as oxidizing agents due to the need for positively charged H+ ions to facilitate reactions with negatively charged ions, which experience repulsion. In acidic solutions, the standard electrode potential for the reduction of permanganate is more favorable, enhancing its oxidizing capabilities. While permanganate can also act as an oxidizing agent in neutral and alkaline conditions, the products differ significantly. The discussion highlights the importance of considering reaction dynamics, such as Le Chatelier's principle, in understanding the role of acid in these reactions. Overall, the presence of acid improves the efficiency of permanganate as an oxidizing agent.
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Homework Statement



MnO_4^{-} + 8H^{+} + 5e^{-} \rightleftharpoons Mn^{2+} + 4H_2O

1. Explain why the presence of an acid is necessary for aqueous permanganate ions to function as an oxidizing agent.

2. Give two reasons for the aqueous permanganate ions acting as an oxidizing agent in acidic solutions.

The Attempt at a Solution



The only thing I can think about is the similarity between this reaction and the Iodine-peroxodisulphate reaction where the repulsion between the negative ions prevents fast reaction unless positively charged Fe^{3+} are present to catalyze the reaction.

So my guess is that since permanganate ions are negatively charged and ions that need to be oxidized like Cl^{-} are negatively charged they repel each other. So a positive ion - the H^{+} ion is needed to make the reaction happen.

I know this explanation is not perfect because permanganate ions also oxidize ions like Fe^{2+}.

So any ideas?
 
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The question is invalid - permanganate acts as an oxidizing agent not only in acidic conditions, it also works in neutral and alkaline solutions, just products are different (compare http://www.titrations.info/permanganate-titration).

Won't it be enough to take a look at the reaction equation and think in terms of LeChatelier's principle?

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I got the question from an A-Level Chemistry textbook in a chapter on electrochemistry.

The question may be referring to the specific reaction and why the presence of an acid improves the the oxidizing capabilities of permanganate ions.

Does it act like a catalyst?
 
I say this because the standard electrode potential for the above reaction is more positive than the standard electrode potentials for the reactions in neutral conditions.
 
Do as I told you: take a look at the reaction equation, think in terms of LeChatelier's principle.

ashwinnarayan said:
Does it act like a catalyst?

What is catalyst definition? Is it consumed in the reaction?
 
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